Why is bacterial vaginosis more common in women who are sexually active? my only 2 partners never ejaculated in me and my last partner was months ago.

Unknown, complicated: BV is overgrowth of mostly normal vaginal bacteria and undergrowth of others. Why it happens isn't clear. BV often behaves like an STD: rare in virgins, more frequent with new or multiple partners. Maybe associated w/ cunnilingus (oral bacteria?). Definitely an STD in lesbians via vaginal fluid; affected women's female partners almost always get it. Once present, recurrence is common w/o new sex.