scientifically speaking, what are the traces of previous sexual partners on a new wife?

Are there still traces of other men's semen in her mouth? what about her vagina and anus?

surely washing in the shower doesn't remove 100% of the DNA, will the woman's skin still have traces of foreign semen?

How many months/years after sexual intercourse will the traces of foreign male semen and fluids be undetectable on the female?