I think it depends on the person. I have heard that full bladdered sex can be very good and highly satisfying. As someone who enjoys desperation/pee fun I can probably imagine that your girlfriend was actually rather turned on by the fact that you needed to go to the toilet. Also I think it's highly likely that being hard and aroused was the only thing that kept you from wetting yourself if you'd drunk as much as you said you had. I know that after a couple of pints I'm struggling and if I allowed it to happen the odds are that I'd wet myself long before I got drunk.

Holding your pee for long periods of time isn't healthy though and certainly if done regularly could cause damage. I doubt whether a very occasional, once in a while, over the the odds hold would do too much damage though. If you're planning any more full bladdered sex sessions I'd make them short ones though. Two hours is a very long time to prolong things if you're bursting to pee. If you want a long sex session it's better to go for a wee first - even if that's not what your g/f wants.

Hope this helps.