Suejan -- There is always hope. Unraveling the male brain, peeling back the layers so that you can gain understanding -- as you know this is a mammoth undertaking which requires immense patience. And, grace.
The most common possible explanations for his rejection:
1) Being a man, he has his own expectations of what a dick and a sex life should be. He's not meeting his own expectations and feels tremendously self-deprecating. This is usually accompanied by a man's own internal narrative which can make him unpleasant to be around, and make it feel like rejection. The main thing being rejected is the man, himself.
2) A secret. Over time, he may have developed a habit that is meeting his sexual needs. Especially if there was a season where, in his opinion, "he wasn't getting any..." There are a number of habits to choose from, but a classic symptom of a man who has a secret is that he rejects his lover without explanation.
Guys aren't known for being good communicators in a relationship in the first place. Our thoughts and actions as men exponentially compound our situations.
Now, about his surgery. When you say "almost a year ago" what does that mean? I can tell you first hand, no sex during first six weeks. Several unfulfilled attempts in weeks seven through nine. And then small sessions toward success. By the six month mark, I was able to have sex with some pain, but it was measurably on the decline.
I'm at the 13th month now, and there is no pain from the surgery.
Have there been any complications post-surgery? You've seen the results, yes? Is there a problem?
One question worth asking to him: If you went through the trouble to get corrective surgery, why are you now not willing to use that thing?!?!
Male sensibilities being what they are, most of us would play possum or ignore the question, or ignore the asker -- particularly if there's a secret.
I believe most men want to confess and bare their souls. But getting those first words to roll out is like pulling teeth. We just need gentle, unrelenting prodding. From his perspective, he will verbalize that you are provoking him (classic deflection from the truth).
Don't be deterred. And, don't be distracted by his early responses which will be smoke screens most likely -- for the average guy.
Besides, even if provocation is what it takes, getting the truth out has obvious benefits. And, there's always opportunity to "make up."
Those are just my quick thoughts from my experience and guys like me that I've spoken with over time.
Sounds like he's worth fighting for! Persist. Don't give in.