Don’t think that makes biological sense but maybe if they know you can cum inside maybe that’s the turn on ? Do they know or do you think it’s a sense ?
I always take the offerings whether being fed orally or getting vag or anal. I never put anyone through the condom ordeal.
My wife hates condoms and honestly I have never used one. We always have natural raw sex and the same with sexual partners I've had in the past. Never got any stds or anything like that either, very clean as is my wife.