Boyfriend takes too long to cum

We’ve only been dating for a month or so but been together 2 months prior. Everytime we start foreplay (we haven’t had sex yet) he takes forever to cum. I’ve been told i give pretty good head and with past guys they’ve came in under 5 mins. But it takes him so long. I have to jack him off, give him head, touch is balls...and nothing. Like damn it gets hella exhausted if I’m being honest, like my hand hurting. Eventually like i just make him jack off into my mouth, but I feel bad. Like why can’t I make him cum by myself? I have a couple times before...it’s just taken awhile. Do you guys have any tips on things I can do to make him cum faster?

Side note: we are 17