Bad sex life

So I’m 18 years old, been with my boyfriend for a year now. My sex drive is very high whereas his was high at the beginning of our relationship and now he hardly ever wants to do it. I get so insecure with the amount of rejection I get and the fact he doesn’t even like me touching him. His excuse is that he’s too tired or just not horny...

When we do have sex, he doesn’t prioritise me finishing, he just makes sure he does and then goes to sleep...

I then am left sexually frustrated as the sex only lasts a minute or 2.

I’ve tried spicing things up but he’s not interested in that he just tells me he has a low sex drive but that’s so strange for someone our age, especially as he used to have a high sex drive, idk what’s going on.

I’ve had many conversations with him but he just isn’t taking anything on board