Most Helpful Guy
There was a question on here I answered from a woman in her 30s wondering a similar thing about her boyfriend in his 40s, except he was going out most nights. My answer was that I thought it wasn't normal for a man of his age, but more for someone in they're 20s.
So I'd say it's pretty normal, some people do it for more years than others, but for most sensible people it's just a phase.
My suggestion would be to talk to him about it and state your concerns. You don't have to sound critical, just concerned. Maybe you can go with him sometimes or maybe you think he's not giving you enough time. Either way, learn to talk to one another :)