What To Do For Foul Odor In The Vagina?

my vagina has a very foul odour like rotting meat, what could cause this as both my husband and myself don't sleep around? I'm 1.76m weigh 70kg I'm 30 I've had this smell before but that was years ago about 8years ago when I was with my ex. I'm in good health and allergic to shell fish and calamari.