Sometimes people stay with a partner they don't want to be with and they get sick. So it may come out in other ways. I believe this happened to my SIL as she is married to a piece of work. Now she is so ill she can't look after her own children and may not be in this world for very long. I think you have to be true to yourself, know that you deserve better and the kids will adjust in time. As long as they have a healthy parent, they will be OK.