Hi, maybe it's a natural thing along with the depression you have. You have 3 kids and that is exhausting in itself. Try to think more positively about yourself, I know your surprised you h is there, but there's a reason. You're a very good person at heart.
Sex is sort of the glue in a relationship, just my thoughts, but it will likely come back to you in time. I'm glad your h understands somewhat. Take care of you a bit today as well as the kids.