People used to say that marriages shouldn't be held together just for the sake of the kids. Now that we have seen the sad results of what broken marriages have done to several large generations of kids, I think we have good grounds to question that. Marriage is not just a contract between two people, IMHO. It's also a contract between those two people and their future children. It is commendable of you to say their welfare is paramount. Also, it is honest of you to say that their dad does love them. Many wives wanting out try to say that the guy is no good to the kids anyway.

If the two of you are getting along friendly-like, that is better than what a lot of kids see. If the main reason you want to end the marriage is because you can't stand being in it anymore, then own that truth. Don't try to sell yourself on the rationale that, if I leave, I am doing it for the kids. It's okay, to do it for yourself, if you feel strongly enough that this is an emotionally impossible situation for you to stay in.

Ideally, you want to offer your kids an example of a great relationship between you and their dad. That dream is kind of dead, or in sore need of resuscitation. Kids don't have to have everything ideal. No kids get that, anyway. You don't describe the kids as seeming to be suffering a lot from the coolness of the marriage. It's affecting them, for sure, but their will be hardships imposed on them, if the two of you split up.

Also, what kids notice changes depending on their age. Right now, this may be kind of working for them. When they are older, they will be more sophisticated about what is really going on between the two of you. If you two are managing to be reasonably polite in front of the kids, then you both deserve a lot of credit.

I'm not telling you to stay with him, just advising that you not kid yourself about why you want to leave. Lots of kids whose parents are divorced grow up just fine. Keep that option on the table. Sounds like you and your husband need to do some serious talking where the point is not to compete in the blame game. Sounds like you might really like to save this marriage, if you can believe he wants to do what it takes to accomplish that. Ask yourself: is he giving evidence of that? Sometimes, "Wait and see." is as good a strategy as any.