It is NOT your responsibility to pay for those kids. Those are NOT your kids. If you partner takes issue with this I suggest sitting this trip out. He is lucky you are paying for your own ticket and meals as he should be paying for them considering you are going to be hanging around his kids and MIL the entire trip and likely doing everything they want to do. It does not sound like much of a vacaiton for you. Also MIL's opinion is irrelevent. She needs to butt out and mind her own business. This is between you and him. If she knew anything she would've raised a financially independent son who is also a good husband which she failed to do since he is divorced, does not respect you and he is still financially dependent on others.

Not your kids, not your problem. There are two people who are financially responsible for those kids: Their two biological parents! The courts agree with me on this. Anytime you pay for those kids it is out of your own generosity. It is NOT your obligation. I highly recommend not going in this trip as it sounds like your being invited so you can be their ATM. It's ironic that he expects you to pay for his kids meals and activities yet you were left to pay for your own plane ticket and transportation. He sounds like a user and an extremely selfish person.

Who is actually responsible and who typically ends up paying are two different issues. 

Of course, MIL thinks you should chip in...my MIL just tried to convince me last night that DH and I should take SSs on a European vacation. That's a nice idea, MIL, are you paying? 

At the end of the day, the parents are responsible to pay for things for their children...stepparents - as we are so often reminded - are not parents, and therefore, should not be held responsible for the finances. If I were you I'd skip this "vacation" because it sounds like it will be a dramatic, boundary-busting, nightmare. 

No matter how many ways this question is posed, and it has been posed almost verbatim several times in the last few weeks, the answer is always "not your kids, not your responsibility". Pay for yourself, including your share of the condo, and make them pay for their own vacation.

Oh, for the love of God!

I mean this is nice way, but you need to think long and hard and maybe get professional help to answer why you let them walk all over you.

SO and I support the children together. From day one I would pay for them to come with us but it wasn’t because SO demanded. If they didn’t come he couldn’t either or we had to wait. I preferred to pay but it was always my choice.

Now we share our income. I make about 300 more than him a pay check after my 401K and his child support are paid so technically I’m providing more support to them in our home then he is. However I don’t see an issue with this because again it’s my choice. SO has NEVER demanded I spend money on the children.

Basically when SO gets paid he transfers 90%+ of his take home to me which I use for bills and other necessities then whatever’s left we use however we like. SO takes VERY little for himself. The kids get most of the extra, me second, and him the very last.

We blended finances from day one of our marriage.  We only had my SS. Our resources supported our family.  That included SS.

Together we have made a life together.  We did not tolerate toxic from my SS's SpermClan. We would not tolerate it from each other.  Our financial success has been for us.  Including raising and including SS.

However, we refused to spend our money on large family vacations.  When we take vacations, at least to SpermLand to visit my ILs we, we let everyone know what our plans are and and let them know that they are welcome to participate. We do not pay for anyone but the three of us.

You may want to adopt a version of this in your blended family situation.

It has worked for us.

Your MIL is trying to control your life and money. And cheep O DH is going along with her.  NOT your kids, No reason to pay for all the cheep people who want to go on Vacstion and not pay for it.  If DH and MIL can’t afford to pay for there own vacation they should stay home until they save money to go.

First of all. You are his wife.  DS is yours or is DH is BF ?  He should be paying for you his kids if DS is not his then you pay for DS.  I don’t understand how you live this way,  beteeen DH and MIL.  Why is MIL going, why do need her in your vacation. I would not want to be around her.  

There nothing wrong that in your heart you want to pay for SK,  if they treat you right.  Knowing it’s lost money.  But to be played that way. How can you love a man like that 

Sounds like your DH is trying to deadbeat and his mommy is on board with that.

He needs to clearly understand that his responsibility is for costs related to himself and his children.. his mother is responsible for HER costs.. and You will be responsible for your own.

Now.. often a child's share isn't 100% equal to an adult's.  For example.. lodging.  If you rent a 3 BR home.. you and your DH share a room.. MIL has a room and Kids have the 3rd room.  Your share is 1/2 of 1/3 of the total cost.  Your DH pays 1/2 of your room's share.. and then full share for the kid's bedroom and MIL pays full share of HER bedroom.  You wouldn't necessarily split it by person though.. because MIL has a room to herself.. and depending upon how many kids etc.. may be more or less than you and your DH that would be splitting a room.

So.. you should pay your share of all expenses.. but no more than that.  Now. if you WANT to treat the kids to an ice cream cone.. you don't put it in your ledger of contributions to the vacation.. it's like a gift.

This sounds like its going to end up being a nightmare. I don't even think I would go on this vacation. If you do, I would make it clear up front that you are not paying for anything besides your own share. If you choose to pay for something for skids, that is your CHOICE, but you are not to be obligated or expected to pay for them. If DH can't afford to pay for them, then he needs to postpone the trip.

I can see how this gets complicated esp, like you said, if you cover things when you're watching the kids by yourself. In a perfect world, I think the bioparent should always be responsible for their own kids, and then you do the favor of paying WHEN YOU WANT TO. I don't think that makes you any less of a family...you can live and hang out together as a family, but all the responsibilities ultimately belong to the bioparents.  

IMHO the core issue is a lack of fully commited partnership including fully integrated finances.  Keeping a detailed accounting of expenditures by household member, worrying about who pays for what based on the genes involved, and diluting the focus on the marriage with potentially trivial issues makes the marriage a difficult one.

Of course if there is abuse, one partner taking advantage of the other, etc, etc, etc... those issues need to be addressed.

It just makes much more sense to me to put the focus on the marriage rather than the adnauseum drama that can overwhelm everyone in the blended family.

Just my thoughts of course.

Yup, easy to say 'not your problem' but what if the scroungers all turn up with no money?  Like mine.  SS26 and SS25 'took H out' on Father's Day.  I drove 150 miles, we all went on a boat trip (H paid).  Got to a pub, bearing in mind it's FATHER'S DAY and neither of the tight b*stards would even buy him a pint.  I was furious.  I slapped a note on the bar and told him to buy a round for us all.  H wanted a 'family' photo and I refused.  He doesn't see his kids often, they are in another country, so H insists on family holidays - despite the kids nearly being 30.  Every holiday, we pay for the accommodation for 5 people, we pay for meals for 5 people (EVERY meal) and I'm sick to death of it.  When the kids were younger, their Mom refused to pay anything (she was always struggling).  Tbf, I agree with her, why the hell are we paying for adult kids??  We are going abroad to meet SS26's fiance.  Again, we are paying for a family apartment for them all to scrounge a week's free holiday.  This is the LAST time.  I am not paying for them again.  I am not a walking wallet.  H is not a millionaire by the way, I have no idea why he keeps doing this.