He couldn't stay hard and couldn't finish?

Ok so i had sex two days ago with a friend that i had only ever kissed before. I know he's had sex several times before and it was only my second time. We are both 17 and everything was fine and amazing until the actual sex. It kept slipping out and we tried several different positions until me on top worked the most. We literally went at it for about an hour and half and i was tired and had already gone into it knowing i probably wouldn't finish but i was also super surprised that he didn't finish.
We used 3 condoms and on the 3rd one he was having a hard time keepig it hard. Is that the reason it would slip out? He told me he almost never finishes afterwards because we just stopped with neither of us finishing. Is that normal? I'm not worried about it being awkward but I just want to know if it's normal that he couldn't finish and stoppig being hard a few times or if it's just that i turned him off by being bad at it or whatever? Im just kind of worried about what it says about me and how i have sex or if its a usual problem? Also we were both drunk, me way more than him though