Newish partner. We've been having sex together exclusively for about 6 months now. He was previously married and never performed oral sex because she point blank refused to let him. Apparently her go to excuse was 'I have heavy discharge'. 
Anyway, she also never have him oral sex, claiming that she couldn't give a blow job to someone she loves.
The marriage ended because she cheated on him... lots. Including his discovery that she'd had sex with one of the teenage daughters friends. 
So understandably he has issues surrounding sex, which we're working through. I give him oral sex regularly, but he never returns the favour. I think he's actually scared! We've spoken about it lots and he tries to diffuse the situation with humour rather than actually taking the bull by the horns. Would this be a deal breaker for you? I'm not sure.
He's otherwise very loving, trying hard to work through his issues, great with my children (yes, shock horror! They've met already!) and generally fantastic. So caring and appreciative of me, my opinions, identity etc.