How do you react when your boyfriend of a year says he doesn't feel the same as you during sex?

We have been together for a year and have been friends for 4 years. I love him so much I can't imagine being with anyone else. But I can't help but feel like he doesn't feel the same.

Recently sex primarily for him has been harder, like he has a hard time finishing. We have talked about it and he says its because he is used to the stimulation and its not because of me. I said that sex is always exciting for me because I'm with him, I'm having it with him the person I love.

And he said he doesn't think of it like that...

I feel hurt... thinking that while I'm with him he doesn't feel those emotions like I do... the closeness when we are together... it hurts... he was my first, I wasn't his but I am his longest friend and relationship...

Maybe I'm being too sensitive he says he loves me he even apologized but I'm still feeling hurt. I'm even worried.

How do you react to that?

Is it okay or is it a red flag?

I need some feed back ladies :(