It is my belief that women having multiple partners and them cumming inside her vagina is the normal and natural thing. And guys want a woman who has already been recently fucked and creampied, especially his wife or partner. It is quite noticeable in our group where the second round of fucking is much more intense than the first. A third round, when possible, can be crazy. I think that's why you hear so much form men about cuckolding/ hot wifeing, MFMs/gangbangs, sperm competition, etc.