IMO, when one gets to the stage of asking should I leave, the answer is generally a resounding yes. That little voice inside us that says things are so badly broken that they cannot be repaired is one that should be listened to. It took me years to come to the same conclusion, but I have only very recently filed for divorce. So I'm not telling you do something that I think is easy - I know how hard it is. But your role as parent means that you have to make difficult decisions for the betterment of your children. You are their role models, and depending on their ages, you might want to include them in your thought processes about why you are making plans to leave. It might be useful to them if they are teenagers so they don't fall into the same trap later.

It's unfortunate that you weren't married as you are not entitled to get a portion of his assets, since you so clearly contributed to his material wealth.

Hamster's advice is very good - start reducing the amount you pay him and start keeping more of the money so you can have a deposit for a new place.

Welcome to PC and I wish you all the best. Take care,
Bub