Can premature ejaculation be cured? NSFW?

My bf and I tried to have sex for the first time a couple days ago. But before intercourse I noticed he wasn’t that hard like all the other times we messed around….and it was taking a long time. He then tried to put on the condom even though I didn’t think he was hard enough.

He put it in and had like a couple pump and stopped…and then put it back in and then he came! He was really embarrassed and frustrated…and of course left me unsatisfied but I tried to comfort him.

The first time I did give him oral a few months ago he came super fast. Over time he has learned to control it better which I am hoping he can do with sex. Now most the time I can give him oral with my mouth getting a bit tired and tell him to finish rather than he accidentally finishing before he wants to.

What I think may cause this
I’m his 2nd partner, and he’s only done it a couple times with his ex a couple years ago. But he said they never had issues with premature ejaculation and sex. They’d do it in different positions, bang and then do oral and back to banging again.
Soo…some reasons I think he may be this way
-hasn’t been laid in over a couple years lol
– he is just really sensitive to touch
– he only jerked off once or twice a month before we started messing around physically (he thought it was unhealthy to do it often lol)

He tried to stop if he felt like he came but sometimes it’s too much. We tried again the next morning…...again he only lasted a few seconds

Oh and do you think a 5–5.5 inch penis is a good enough size to make sex feel good? I couldn’t tell with his because he wasn’t even hard all the way O.o and couldn’t for some reason at the time….