I have a 16 year old son who was abandonned by his father (no maintenance) et lives with me full time. He recently started working, a few hours Saturday and Sunday on minimum salary.
My DP has 2 adult children (18, 22 and 24) for whom he still pays maintenance. The 18 year old still visits us EOW.
We have a 7 year old together.
We have a common account where we contribute 50-50 and the common expenses come out from there, so my DP considers that he pays for my son because his contribution covers half of his food and electricity bills. I pay my son's other expenses from my personal account. I also pay some of our common child's expenses myself and sometimes pay for some of DP things, just because I'm the one who likes shopping. DP never shops for anything interesting for me, so I never get anything personal from him. I also invite us to restaurants occasionnally and contribute more if we go on vacation. That's sort of my contribution because my DP pays for my son. I also contributed to our common son's study account all by myself. DP says that he has no money to contribute because he pays for my teenager (doesn't matter that his 24 year old should have been financially independant by now, but he's taking his time travelling instead of finishing his diploma and still needs at least 2 years to get it and the 22 year old didn't even enter the uni for the same reasons).
I also agreed to buy an expensive electric car so that my DP could go pick up and/or visit his children in another town and he still uses it for work purposes and discounts expenses on it as a freelancer. I use it too, but only when he doesnt need it. We paid for this car 7 years 50-50.
I also can't imagine how we would calculate my son's portion of food and electricity. Not to mention my DP's daughter's, even if she comes less often, if my son would pay for his expenses, why should I pay for my SD? Just by principle. I think it would be super messy and ridiculous. And disgusting.
My DP always made somewhat more than me, but this year has been more difficult for him, however when I made less than him, I just managed.
Any advice on how to manage this situation?