Okay, I've searched high and low for an answer to my question. Most of them are: a) All about STDs. Me and my girlfriend are strictly monogamous. We have no other sex partners, and no STDs. So there is zero chance of infection. b) Telling me to abstain. Well, my girlfriend and Jesus have decided to see other people. I'm on the pagan camp. So, abstinence is nonsensical to us. My question is very simple, but it seems that accurate answers are hard to find: Will me cumming inside my girlfriend (who's on the pill MonoNessa) reduce the claimed effectiveness of 90+% of the pill?