Oxytocin is produced through orgasms, but also through basic sexual contact, I'm pretty sure. I don't know that it necessarily matters whether she is having orgasms or not, from the standpoint of chemical bonding.
Ron, I don't know what most women would say, but I know that, up until now, the best sex I had was with a guy who rarely made me orgasm. I enjoyed the sex very much - however, I was frustrated because we were not having it nearly as much as I wanted, and it didn't last as long as I wanted it to. That said, I never would have cheated to procure more fulfilling sex.
I think it's great you're concerned about your girlfriend's sexual satisfaction. Have you asked her what she likes in bed, and what makes her come when she pleasures herself? I know that some of my former lovers have been very frustrated that they couldn't make me come when the issue, for me, was not so much physical as psychological. I've found that no matter how good a guy can make my body feel, no matter how long he can last, I need to be mentally stimulated in order for me to climax - which means I need to see that my partner is very turned on, and I need him to verbally (or at least vocally) express that to me. The more talking, the more noise, the more he can get inside my head, the more likely I am to achieve an orgasm. But all women are different, and the issue may be different for your partner. Try taking some time with her to figure out what works for her... if nothing else, she'll be over the moon that you cared enough to try.
