>>725177054
They're not really comparable. The reason you wouldn't want food or drink someone else has partially consumed is that there's a risk of foodborne illness, and gross residues in general.
Whereas, odds are, you're good as long as you're involved enough with someone to trust that they don't have any secret kids or are hiding STDs from you.
Of course, that only really applies when you're talking about a woman who's only had one or two prior partners, or has otherwise just recently broken off a long term relationship.
If she really did have that many previous partners, particularly in a short time, that doesn't speak to some intrinsic loss of value, but it is an indication that you're going to get tossed to the wayside yourself, no matter how much you try to make it work. Which is a separate problem.