I ask the question because my partner and I are both mid-40s and I don't know what's normal for people our age.

I have a couple of friends who I just meet for coffee or lunch every once in a while and that's always been the case. My partner, on the other hand, did the same for the first 18 months of our relationship but the past couple of months he's reconnected with a group of guys nearly 10 years younger than him and all of a sudden he's going out drinking nearly every week. He always told me he hated noisy, crowded bars and wasn't someone interested in going out to get drunk, so he is turning into someone he said he wasn't. I thought we both enjoyed the quiet life but I'm becoming quite uncomfortable with how much he's changing.