Hey OP,
I can pretty much guarantee that it's not because he's not attracted to you. As an authority on the equipment (I have a set) I can firmly state that while attraction will play a part in getting and maintaining an erection, finishing is literally just a case of "penis + friction + time = orgasm"
So it'll be a case of one of the items in the first half of the equation being missing.
Time - If he's stressed out and tired, he's probably flagging before he's ready to come. I've been there, you want to get over the finish line but you just can't find the last bit of energy to get there and eventually you give up.
Friction - This one should really be "feeling of friction". Could be one of a few things. Either there's more lubrication than usual, he's a bit more desensitised than usual (whether through masturbation or a few beers), or the position isn't great.
Penis - I'll assume this one isn't missing!
You mention oral isn't doing any good. It's unlikely to. One of the reasons men like blowjobs is because they're spectacularly bad at making us orgasm. They feel good, but not so good that they'll tip us over the edge too quickly. If you want a man to come quickly, your best bet is your hand. Hand is quicker than sex, which is quicker than a blowjob.
Alternatively, if you want him to orgasm during penetrative sex, then doggy style is most mens kryptonite. It's relatively low effort for him compared to missionary, and has the advantage that you can do some of the work too by rocking backwards. It's also high friction.
Hopefully I haven't gone a bit TMI and the above is helpful!