Comment! Settle this debate

So ladies, I need your honest answers.

Me and my man are not trying but not really preventing, we wouldn’t mind another baby. (PO+no birth control) but two days ago he finished inside during my ovulation window. I told him that one time is enough to get me pregnant but he seems to think one time can’t get you immediately pregnant. He says you have to have intercourse frequently (every 2 days) for me to get pregnant because that’s when the swimmers are fresh and optimal.. I can’t with men🙄 can you ladies please comment if you got pregnant from one time so I can show him😂👏🏼