Have only skimmed answers, so apologies if I'm repeating what has already been said, but OP, you 'not being in the right head space' is reason enough to not be able to orgasm, and you shouldn't have to pretend.
Men really don't get that women need that to be right too, a lot of the time, rather than it just being a physical response to stimulation (added to which, mother nature rather unhelpfully put our clits on the outside, not on the inside where the penis goes hmm)
But so many other worrying things in your OP too - he won't give you oral (and believe me, most men - the vast, vast majority of them, ❤❤❤giving oral to women, so you've had some shocking luck in that department) and now you are left with lying and faking.
Sometimes I'm not in the right headspace to orgasm through oral too (although I still really, really want to have sex with my DP nonetheless) but he loves going down on me, absolutely can't get enough of it, so he knows he can do as much as he wants of that (even knowing it might not work because of the whole head space things), and I still get to have all the lovely feelings on his mouth doing what it's doing!
But when all the pieces are in play, head space included - oh boy, he's very good at what he does, and yes it's always been 'lady first' in our relationship. We always finish with piv with all the wonderful extras of my scent all over his face, and him turned on from going down on me, and kissing etc. I love it, even without my own orgasm. I certainly couldn't fake it either!
I'd be far too embarrassed to pretend to make the noises I make when my clit does work 
(noises that I realise are again, totally different to the ones I make when I use my bullet) so yes, he'd know if I'd really come or not... and I know exactly when he's about to come too... isn't that one of the most erotic parts of having sex with a long-term partner, being that in tune with each other that it's still amazing several times a week, even after so many years?
Oh OP, I've not idea how you're going to 'change him'. I'm not sure you can if it's this ingrained in your relationship. But you've still got a lot of living to do - do you want to do all of it with a selfish partner who's shit in bed?
Or would you rather than a partner who puts you first, cares about your pleasure before his own, and bloody well knows without asking whether you've come or not?
I'd go for the latter if I were you.