I'm 25 it takes me a very very long time to reach orgasm sometimes and I'm not sure of the reason. I have a few theories but I'd like other opinions.

So, I am a porn addict. I masturbate frequently when I have free time. Usually once before going to bed during the day, although on some days it will be more. When I have trouble sleeping I will also masturbate which will usually do it for me. When getting myself off, it usually takes about 10-15 minutes and I get off usually not an earth-shattering orgasm, but an orgasm nonetheless.

Now, when I am with a woman, often I will have trouble reaching an orgasm. For example, my last date was with someone TOTALLY hot. definite a real turnon and I would get hard just thinking about her. So, she performs oral for a good 20 minutes and nothing. Felt good and getting some decent build up at times but not really that close to orgasm, then she gave up. I perform oral, she orgasms no problem. We cuddle for a bit let her rest. She then does some oral before getting me in a condom. We screw for 30-40 mins where I think my back was almost thrown out, she's tired out, and I have no problem keeping it up the whole time, but still no orgasm. Eventually I was too tired and so was she. She tried to finish me off with my hand, which wasnt working, and then she starts kissin on my ear and my mouth while I try to finish myself off and it still doesn't happen although I tell her it does. This happens with many girls I've been with generally on the first time I'm with them. If I do reach orgasm tho, it's usually one of those extreme earth shattering strong ones.... it just doesn't always happen.

So, my theory is maybe i need to cut down on the masturbating. Any other ideas or suggestions or anything? thanks

PS - I heard also there may be some complications due to the fact that I'm diabetic.