The first thing that popped in to my head is, if he doesn't want to deal with monthly mood swings, start dating guys.

If you want to stay together, this is going to take some open communication on both of your parts. Unfortunately, from what you've said, he doesn't seem too willing to do that. If he could at least tell you *why* he wants a 4-day break and you find it's something acceptable, then maybe it could work. I think it's really unfair of him to "diagnose" you bipolar because you're PMSing though. Cripes! I can go from hating my pimply, salt-craving bloatedness in the morning to being able to at least deal with it by the afternoon. Does that make be bipolar too?