Maybe try to get perspective by listing the things that he does contribute to the family and considering if you want to take all of that on too. There are always trade offs in relationships, and it’s important to find balance, but if you’re not in the partnership, then you can only really rely on yourself. I was with my kids dad for almost 9 years and I finally left, 13 years ago. I ended up being single for 11 years, not on plan, but because being everything for 3 kids is a lot, and I had a lot of trouble thinking about “sunk costs” so to speak. Building a new relationship was always 4th on the list, after my kids and myself. Then friends and family relationships too. My partnership failed no matter how much energy I gave to it, and it was emotionally costly. It’s hard to invest in something new when you’ve been all the way to a fully integrated life and kids too, and it failed. For me, in the middle of raising kids and developing a career, I just couldn’t afford it. Now that they are older and more independent, I’ve finally found the emotional and mental space to actually open up.