Tips for sex after surgery?

i recently had my ACL rebuilt....my wife wanted to wait until after i was feeling better before we had sex again, and we still were unable to do anything to rigorous (we waited about a week and a half). it did take me a while to get hard, and we stopped after about an hour because she was getting sore....my mentality with sex is that if it is uncomfortable for her, than there is no point, because we are both not enjoying it. still, after an hour, i was unable to have an orgasm. i attribute it to the meds the doc put me on (percocet and valium). since being on those meds, i have had almost no sex drive either. i was wondering if anyone else here has had similar issues and would care to share experiences or tips to get around it. thanks