If he likes her so much, then cut it off with his current woman and go move on to her if she's just that bad. He needs to give his current girl a chance to move on if he can't live up to what a commitment entails.
Some cats love playing a losing hand on here. "Man, I got an interview for an $100,000 job tomorrow. There's a possibility of a drug test, but I feel like smoking. Should I smoke some weed?"
If you got a woman that's getting everything right, no drama, cooks, cleans, listens, and doesn't need an emotional circus to operate, introducing some drama via a one night stand is nonsensical.