Hi, there: Thought you might like a guy's perspective on this. His situation may be caused by several different factors concurrently, although this is just a guess on my part since I don't know all of the specifics. In any case, his sex drive may have declined somewhat since you first met. If he is on any kind of medication, that could certainly affect the sensitivity of his penis, making it very difficult for him to climax when you are having sex. As a partial means to get around that problem (if it actually exists), he may have turned to porn to get the extra visual stimulation he may need, along with manually pleasuring himself in a way that feels best to him, in order to get his release. He may have gotten so used to getting off by himself that he has totallly lost interest in sex with you. There may be some other underlying problem as to why he does not want to have sex with you, but you may have to get professional help as a couple to figure out why. If you can get him to stop watching porn and/or masturbating for at least a few days, perhaps you can try to have sex with him and see how it goes. Guys have a physical need to release every so often, so I would think that he would be able to climax with you after several days of letting it build up. Let us know what happens. I wish you all the best with this. If you'd llike to send me a message and discuss further, I'd be happy to try to help.
Is there a possibility he is cheating?