If being an evil stepmother means you speak up and don’t put up with bullshit then proudly own the title and tell the little darling to grow up and suck it up. You aren’t leaving anytime soon so she better deal with it. Be a bitch to her. Don’t let her step all over you. 

I think confronting emails (no matter how much your therapist liked it) can backfire.  There is no way to soften the delivery.. to change the explanation if you find the other person is misunderstanding your intent.  The written word sometimes can come out more pointed and without the emotional inflection facial expression etc..

I think it would have been much more effective if you had tried to address this in person.. perhaps by  making a point when she visited to say.  "I'm going to be in the kitchen shelling peas.. please stop by and say goodby before you leave" 

I think there may also be a little bit of mismatch in expectations. You say that your relationship was always challenging.  I'm sure that there were issues on both sides of the equation... I'm sure you did your best.. as most of us try to do, but sometimes in the end, the SM is "dad's wife" and the kids aren't interested in any more relationship with her than that.  You don't say what the challenges were.. so we don't know if they could have percieved you as changing their lives negatively.. don't know if you tried to be their mother and they didn't like that.. don't know if you constantly complained about them.. don't know if they were horrid little minions of their HCBM..

In the end, as adults, they don't seem to want a close relationship with you... then you send them a letter accusing them of treating you badly and causing them pain.. honestly.. they probably just didn't feel they owed you more than being civil and got mad that they were called out on it.  Did the daughter thank her father for visits?  Maybe he raised ungrateful kids (in which case you can enjoy not having to spend time with them)? 

I don't know what the solution is...  You could try to broker a truce?  perhaps invite the daughter to lunch to talk?  I dont' know.. what do you want?  Do you expect your DH to snub them and not see them or force them to invite you to something.  They are adults and they can behave on their own independently of their father's wishes.  I'm sure he wishes the relationship was better... but he probably feels he has limited power to change this and isn't willing to dump his kids... but he will leave you alone while he sees them.. but the risk of losing you seems less likely than him losing his kids.

My take on this crud is “eff off bitch”.  I do not want toxic ahole people in my life.   And if my DH wants to be a toxic ahole bastard he can leave too. 

Life is too short to deal with toxic people. 

Looks to me like your husband HAS picked sides. And it's not yours. Sure, I get that he wants to see his daughter and grandkids. But it would sure be nice if he insisted on at least basic civility toward his wife. His kids don't have to LIKE you, but they should at least be respectful of their father, and that means being respectful of their father's wife.

Do you have to accept things? No,no and no. Why should you? How would your DH feel if you did the same thing to him.

You are not the evil SM. Your SD is being evil by playing exclusion games with your DH. Purposely excluding a family member is wrong. Your DH should not sit back and do nothing about it. A good husband not only invites his wife on family vacations, but doesn't go if his wife is being left behind because a disrespectful SD does not want her to. 

Seems your DH does not want to upset his evil DD. He should man up and not allow this toxic girl to ruin your marriage.

Let your DH know how you feel and ask him how he'd like the same treatment. Tell him you would like to take a vacation with him.

your SD is most likely using the gskid as pawn to manipulate your DH. My adult steps use their kids the same way. It is so obvious and sickening. 

Stand your ground and don't let these toxic steps exclude you. It is wrong. If they want to keep excluding you, your DH should discuss this with them. A good husband doesn't ignore when people in their family treat his spouse like dirt. It sounds like the steps have been treating you poorly for a very long time. 

Let him go, four days is nothing. During that time hire someone to change up something in the house, go visit a friend, relative, have a party, do something other than mope around because DH is off w/his rude daughter.  Let them have each other. Be happy and busy when he's gone and enjoy the peace.  

You didn't want to deal w/her rude behavior anymore, you got your wish.  

This post resonated with me so much. When I eventually spoke to TheX about OSD and her wedge creating tactics he took her side and labelled me as evil. Where do you go from there? I thought about phoning/writing to OSD and appealing to her good nature in seeing things from my perspective- but in the end thought better of it, and here's why. She was waiting for it! It was what she had wanted all along- to have me grovelling like the rest of her manipulated family, and I hate to say it but you played right into her hands writing that e-mail as it now gives her carte blanche to have daddeee to herself and make you feel second class to their first class enmeshment.

I think you have two choices here: One, leave them alone in their relationship and build up your self-esteem, focus on yourself (look up Sammigirl on here) and live your own life within the confines of your marriage as if SD didn't exist. It is called disengagement and if has worked for lots of people on here.

Two: talk to DH and try to get him to see all you have done and put up with for twenty years. Tell him how unhappy you are and if he does not begin to see what his enabling of his daughter's behaviour has done I would make plans to leave.

In the end TheX and I could not have a relationship in which he constantly ran after his little girl/grown woman and buried his head in the sand rather than regarded my feelings about this at all.

It is five months since I left him- he does not want me back and chose his children over me. I am remaking my life and it is great- they no longer dominate my thoughts and I am in control of my own life.

Let us know how you get on.