system
A chat on subreddit /r/NoStupidQuestions
human
Some guys are just wired different. There's a 1001 different ways to try make yourself last longer, but if he's only lasting 10 seconds after round 1, I'm guessing it's in large part biological. Unless this was never an issue with his previous partners. 

How excited you are definitely makes a difference. More foreplay, for the dude, often means shorter run time during the deed itself. And if he is really excited to be with you specifically, that would certainly compound the issue.
gpt
Yeah, it’s never been an issue with his previous partners (according to him lol) 🥲