He does not live with her. He sleeps at our house every night but a lot of his time is spent there in the evenings. He has shared parenting with his daughter from his first marriage so he gets her 3 weekends a month and every other week in the summer.

Women almost always get the children, child support, house, and often alimony. The court system is there to protect women and give them advantages. Get a lawyer and he'll get everything for you. You'll make 100's of times back what you spend on the lawyer. Best investment you can make. Just don't work and don't get remarried (boyfriend is fine - they pay for things anyway, so good to have around). It's a winner take all system (kids, money, house, etc.) and statistically, women win 85% of the time. That's why women initiate most divorces and men have much higher suicide rates after a divorce. Go after him!!! Just use the magic words to the judge "it's in the best interest of the kids" - the judge will roll over and give you everything.

The default parental order is 50/50 for each parent. You both have parental rights to your child and having both parents is the most beneficial. I would start working on a parenting plan with a lawyer.

The way your child feels about his grandparent is irrelevant, however. Nor is where your stbx will be living. That's his choice and he will make his own life decisions in the future, just like you'll make yours. Concentrate on what's important. Finding a way to work out a shared parenting arrangement with your child who needs both of his parents in his life.