What is going on here... and what do I do?

[LIO]

Well go figure.. I received divorce papers today.

He doesn't want to be married, he's tired of 'this'. He can't explain anything. Back to square one except now I have a deadline.
The good news is that he most likely has to stay here now that OW is done with him.

I'm dealing with someone who is severely depressed. He doesn't want to see a counselor and he is always going through this each year. This is by far the worst year. He admitted that he had sex with the OW to feel better briefly - and of course it didn't work.

So now I'm on a limited time frame, and this [censored]. I don't know what I need to do. He's not going to snap out of this depression in time. And he's causing a lot of chaos. HE made some offhand comment like "well, I guess if divorce doesn't work, we could get remarried" or some joke about splitting custody like "Looks like I'll get S's legs and knees, you get shoulders and stomach". I don't find any of this funny and now that the court will be involved I really don't find it humorous.

I don't know if this is even worth it.. I like him 6 months of the year, and then 5-6 months he's going through some issue. I mean I can just see myself having to worry about every girl he is around wondering if they will turn into the OW. But I really don't want to split up my S's time. I feel awful.