Help! Beyond desperate!

Been with the same man for 3 yrs (was married for 8.5yrs before), just now having problems with smell and waaaaayyy long periods (mind you I'm 37), from lasting 3-4days to now over a week. Also noticed a bad fishy smell down there I've never had, I have no insurance, so need some advice on what to do, or possibly what's going on. Trust that the guy I'm now with would never and has never cheated... NEED HELP NOW!