How come it takes men longer sometimes to cum than others?

Ladies I just don’t get it!!! Lol about a week ago me and my man were having sex and he came in 2 mins. It was terrible 🤣🤣🤣 then like 2 days later we tried again, and this time it took him for ever. We actually had to put in so much work for him to cum I was getting tired lol we did the same position both times and yet two different outcomes. What’s the deal with that? I feel like I always cum from certain positions yet for him it’s different