So my boyfriend usually only finishes in me at the end of my cycle a few days before my period & the rest of the time he makes sure to pull out (not the most responsible but we’re in a good space where if we did have a kid it’d be okay so that’s why we’re not super protective) but I hadn’t seen him in like a week due to a vacay & when I got back we had sex & he finished in me without thinking/asking , I start my fertile window in 4 days... I know sperm can live longer , does anyone know a % of chance of that happening ? Or just an idea