The only way to get it off your plate is to not do it.  

B/M has a mother -TT.  If she is dysfuntional and incapable - that has to not be your problem. I know its hard because you have a very vested interest in trying to launch B/M.  But - your actions will not help and will really only backfire on you.  

So just disengage.  They have registration?  Oh, that's nice.  Good luck.  Why are doing this still?

My bio kids have never been good about saying "thanks", probably becuz I'm not good at it, either.  I know they ARE thankful of what Ive done over the years becuz they show it in their actions and thats all that means anything to me. So, if it were me, I probably wouldnt notice but obviously, spoken thanks is quite meaningful to you.  I guess what I'm saying is, its a "manners" thing.  Obviously, we all hope our kids have acceptable manners but they are more important to some than others.

I hope I'm not coming across as someone who raised ferals.  What I emphasized was treating others well, being honest, being stable and gaining independence.

It's hard. I know personally how hard it is to NOT be involved, especially when you KNOW the parents can't/won't do the work for THEIR kids. Still...you simply must stop doing. This is your DHs job and the BM's job. No one else. You will never be appreciated or thanked for anything you do; rather, most times, it will get turned on YOU. 

Here's an example from when I was still involved with DHs kids. Took youngest one shopping for clothes. Spent about $400 on him. Months later, we had to go "rescue" him and found out he had a bench warrant out for his arrest...didn't show up or pay for a speeding ticket. When DH was angry with him, he looked at me and said, "It's your fault. You made me late when you took me shopping." HUH??? LOL 

Seriously....nothing good you do for your SKs or that BM will EVER be credited to you, so just stop. Then in the future they can blame the right people. The parents. Big hugs. I know it's a hard road.

Disengagement takes many forms and many stages. The final stage is not just stepping back from doing anything but also stepping back from caring. This part is the hardest because everybody has a natural curiosity about the drama. But sometimes the train wreck is happening so slowly that the best thing to do is just turn away from it.

I'm sure we all work with a person that only seems to want to get tasks out of their inbox and into someone else's. Unless it's something that absolutely needs to be done by you, then you just pass that right long to someone else. 

Neither your dh or TT use the internet? I mean... I guess I understand (sort of?) if people are elderly and never had to use computers at all when they were working but how can an adult not know how to use the internet?

The simple answer to your question is... You just don't do it. If DH and BM need the information and can't figure out how to access it online, then they can be resourceful and contact the school. If they can't muster up the energy, brains, motivation, etc. to do that, then I guess the information just isn't that important to them. If it comes at SD's expense, then oh well. What would DH and BM do if you weren't in the picture? Probably exactly what they do now -- absolutely nothing. You can't care more than the bioparents. Thank you for coming to my TEDTalk. 

However, you don't do it, by not doing it. I know, the usual Rags' over simplification. However, if SD won't solve her own problems and BM and Daddy are uninformed, that really is not your problem. Let them figure it out.

While I was highly involved as SS's dad, I rarely had to do the deep dive stuff that  you just did. His mom was all over it.  I attended just about every event, registration, PT conference, etc.. but I was purely a participant not a responsible party.  I took him to Doc appointments, school functions, etc occassionally without his mom when she had schedule conflicts.  But... the real work was already done.

Get your head out of the broad care space and into the self care space.  Let mommy, daddy, and the increasingly toxic spawn figure it out.  

I know you are invested. 

STOP THAT!

Take care of  you.

Only 1 year and 10 months and then she as an adult can do ALL this chit on her own. 

I want to kindly disabuse you of this notion.  Turning 18 is not going to magically undo all the inadequate parenting she has received or make her into an adult.  Given the track record for the older sister, I don't see things changing much.  She won't have the skills or motivation.

Ideas on how to get things off my plate?

You tell me.  What are you getting out of these activities that always seem to end the same way (you do something that doesn't belong to you and then feel upset because it isn't acknowledged)?  Are you trying to control outcomes?  Get points with your husband?   Because practically, all you have to do is stop doing these things - you're aware as you are doing them that they won't end the way you want, so there has to be some deeper reason you keep repeating this pattern.

Yes.. one forwarded email to TT.

"Here is your email from the school, not sure why they have this email. you should change it to your own"

You already had gone above and beyond taking care of your DH's obligation.. you were under no obligation to do it for TT/BM.  

Because.. you know what would have happened if you didn't step in?  B/M would still have ended up registered at school "somehow".. 

and not sure why you expect B/M to thank you.. you were doing something for her mother. she didn't have to thank you on her behalf.

It's not like you took her shopping for 500 dollars of new school clothes.. that might get you a thank you.. I can see her not being overly enthused about online registration stuff.

but again.. why do you do these things?  and "because they won't".. isn't a valid excuse.  all you are doing is perpetuating their learned helplessness.. so you are actually causing harm when you try to fix things instead of letting them figure it out. simply forwarding the email is all you needed to do.

You do this because you are a good person, always hoping it wil mend the situation, and you will be recognized. EXCEPT the folks you are dealing with are not inherently kind people like you are. So the result will always hurt YOU>

Please stop doing for them , they dont deserve your light lady. They are darkness.

Yes you should of got a thank you from SD, thats what decent people do. In reality you were doing this for SD. This helps her.  Again they are NOT decent. SD is never thankful for all that you do.

Yes CLove- I also went above and beyond and now the SKIDs are adults and it never ends...step back and put your resources towards yourself. I am about to fall into the trap again with a bday coming up and I decided to just pass along and let DH handle it. It's his job not mine. However I am already planning a fabulous massage and facial for myself. Would have used the money on the SKID but realize it will not be acknowledged nor met with any kind of gratitude. Self-love is where you need to go. 

I'm starting to think you do this for attention. I really do. 

Have you started seeing a therapist like we have all told you to a long, long, long time ago? You need to figure out why you keep repeating the same mistakes over and over and over again, all while knowing exactly the end negative result that will happen.

Agree with everything everyone said above.  Don't do it by no doing it!!!

But I'd like to address the lack of a thank you.  That was not (in my mind) a thank you situation.  You did not help SD.  You helped her Mom.  And SD could care less.  Her job is to go to school, brag about any good grades she gets, hide any bad grades she gets, and try to join as many events, clubs and festivities that she can.  Oh yah, and graduate.  Nothing you did helped her.  You told her...."Here's some information your mom needs, make sure you give it to her and xyz".  My kids, who are incredibly polite!!!!...would have said "OK".  or "All Right".  or "Will do".  You didn't do SD a favour.  You didn't give her a gift.  You gave her a task to do.  You wouldn't expect her to say thank you if you said "Clean the bathroom after dinner please".  So why are you expecting a big Thank You for telling her to give her mother information that helps the parents to check in on her and does nothing for her?

BM needs to do these things for herself.  If she doesn't do it, it's because she doesn't care.  So you made sure everybody knows that they're dropping the ball and good ole' Clove is here, and they'd better be grateful because the world would be a mess without you.  Your DH is grateful (which is all you can expect, and is good!).  BM now has the login information spoon fed to her, which she will ignore, unless she wants to take the opportunity to look good to a teacher.  And then you'll be annoyed because she does nothing all year and then swoops in with comments on the portal that you facilitated.  Drop the rope!  You're making yourself nuts now, and facilitating their ability to make you nuts on an ongoing basis!

TL:DR....No thank you is required when you tell someone to do something for someone else.  And stop being the only parent to do things.

You don't need to stop interacting with skids ot doing normal family things for them. You are a family. But just don't take on school obligations. Especially not for kids' other parent! Your DH's ex of all people.

Your hands aren't tied at all as you have zero obligations registering anyone for school. Plenty of people are computer illiterate, have  no WiFi and have no electronics. But everyone attends school so everyone's parents figure it out one way or the other. Schools provide assistance tk those who can't figure out registration. You aren't the only person who can enroll kids to school. School will provide help. SD will be able to attend school regardless if you enrol her or not 

Just do other things with skids. Not taking on parental obligations.

You really need to stop sending and receiving school emails, checking grades, contacting teachers, signing skids for school things etc those things really need to stop as those are specifically parental tasks. Do other things. There's plenty of other stuff you could do with them or for them if you want. 

"How to get things off your plate?" They were never on your plate. You yourself keep putting these things on your plate. You are making a choice. Just stop. 

I still think that good therapy would be so helpful for you to figure some things out. 

I know that when people ask you for help, it could be hard to say no. And after you helped, they don't even say thank you. That's understandably upsetting 

but you yourself called SD and did all these things for her mother and you sound proud of the things you did. But that wasn't something you had to do or was asked to do at all. As with all other parental tasks you take on 

I've met few people in my long  life who do things like that. Do things no one wants or asks of them or things that aren't their job at all and then expects ton of acknowledgment. 

I think that perhaps you don't feel sufficiently acknowledged, loved and appreciated in your life. Not by skids. But in general you don't feel important, accomplished  and satisfied professionally and personaly (certainly not by your DH). When you do all these things that you should not be doing, you feel important. You sound very proud when you describe things you do in every detail and your big special role in completing those tasks "I am the only one online, I am the only tech savvy, I emailed, I checked, I signed her up". Subcincously you feel important and accomplished.
 

But then later you always feel deflated because that sense of your own importance doesn't last as you aren't being sufficiently thanked or appreciated for all the things you do (even things you absolutely shouldn't be doing).

also it's possible you don't have much control over your life, going by what you post most decisions aren't made by you, neither at wotk nor at home. when we do things for people (things we shouldn't be doing), we feel sense of control. It's a good feeling. But it doesn't last though. It typically ends when task is completed because it's really an illusion of control. Not a real thing 

of course you are a good person and do these things to help but on a deeper subconscious level there are more serious deep seated reasons for you to keep doing all of this. That's why therapy would greatly benefit uou. Not sure why you avoid it. It could really help you. There is more to all this than stepkids issue and just wanting to help. It's deeper than that.