Re: sex issue after divorce
What makes you think it is not physical? In my opinion, it could be both physical and psychological. Maybe you are somewhat stressed from overwork. Maybe you are not getting enough sleep, eating a poor diet, what do I know? Are you sure your health is ok, to begin with? It's quite strange that you can't climax even with masturbation. This makes me think there could be some physical connecton, you see?
Maybe it is also the novelty of this experience, although usually new experiences would make sex even more pleasurable and easier. Well, not always...
I can think of two things for you to try out:
First, abstain from sex (including masturbation) for a long while. I know this can be somewhat painful for you, but take it as a bitter remedy. I hope you can negotiate it with your girl-friend. In the meantime, get plenty of rest, invest in a healthful diet, take care of your body.
Second, when you begin again, start with "solo" and then only foreplay (difficult I know) until you are ready for the full range.
There is a third way: for conscience's sake, talk to a doctor.
Best of luck.