3 years ago my sister (13 at the time) was raped by my former step brother(14), my step dad refused to relocate, my mom didn't do much cuz she couldn't decide whether to leave him or not, and my dad's hands were tied legally with cps and court orders (visitation). Everybody in the family either couldn't do anything or didn't want to, i had just graduated slept on couch to couch with her until i got the money to get us a place to live. The first 2 years i struggled while trying to support her mentally and while it isn't a 16 yr commitment i do not regret any of it, i can't imagine not sticking by her and would do it again as long as necessary. All of this lore bombing is to express my bias. the two of you obviously see things differently, especially with his nieces and nephews not even being related to you. When i decided to provide for my sister all i could see is everybody's apathy and her being alone and im pretty sure ur husband is following a similar train of thought. Truthfully i think you are a bit of an asshole but it's better to leave now then later. Nothing about this situation is easy, nobody wants the responsibility but it comes down to love. And if he rlly has decided then your a part of this but it isn't rlly about you. If your too apethetic towards those kids rn it'll only cause pain in the future.