What Causes Bad Odor From The Vagina?

hello there i have a smell coming from the inside of my virgina but not the outside i have never smelt before only one about a mounth ago? do you know what it could be ? after having intercourse its more apparant my parnter of 8 years said its unpleasant smell sometimes fishy smell, so i inserted a finger to test it for myself and as i wipe my finger on a tissue there is a peachy colour on the tissue what could it be, many thanks