I see the comments, and I see why normal humans despise us tainted by the NTR, but what can we do? We have fears.
Also, in my particular case, I'm just bored at this point. Get a romance story. "Need drama". Add a third person. Why? I get it, these things happen. And so do other 50. There are MANY ways to progress the story, why do we default to triangles and jealousy?
Same here. It's a fluff story. OF COURSE they've both have partners before. It's highly uncommon (cries in loneliness) to be a virgin after college. But just because we know exes exist doesn't mean we want to see them appear. It's literally the opposite of fluff.