Why can't I make him climax?

I’ve been seeing a guy for almost 10 months now. We have great sex and we both have no complaints but there is one problem that has been bugging me since day one. I can’t get him off during oral sex! I have never had any previous men complain in that department. I consider myself quite good at it. When I give him oral sex I try almost everything!! He moans and says it feels really good. He even says that I’m amazing at it. So why can’t I make him cum? I have even asked him numerous times to tell me what makes him feel good..and what makes him cum. He doesn’t really answer and just says “keep doing that” or “I love what you are doing now”. Then why can’t I bring him to that climax? He can get himself off though. Which really makes me angry sometimes. After I spend AT LEAST an hour deep throating…sucking…licking…stroking…spitting…talking dirty. he still doesn’t get off! he likes it when he strokes his own penis and I keep my mouth there and spit and suck until he cums. But really that is him getting himself off.

I love to make men cum…I like that they get to feel good and that I did that too him. Now I have found the person I might possibly have a long future with and I can’t make him feel that!

Any suggestions to help me would be amazing!!!

Thanks so much for reading :)