Hello again,
You have every right to know why he’s on dating sites while dating you, so he really doesn’t have a reason to be offended. But if he IS offended, it’s probably because he feels his privacy was intruded upon. You did not purposely spy on him or rift through his computer; your girlfriend accidently saw him on dating sites. So if he feels betrayed, don’t feel guilty, and explain to him the situation.
Oftentimes it’s better to ask preliminary questions before the actual question. So maybe ask him how he feels about the relationship, how committed he is, how far he thinks it’ll go, etc. If he answers he is fully committed and happy, his explanation as to why he periodically checks dating sites should be interesting. Since you’ve had the conversation once with him before, ask him, as if simply out of curiosity, if he still goes on dating site, if he still checks on his wife, etc.
If you are finding it difficult to talk to him, maybe wait until the next time he does it, that way the subject is relevant and easier for both of you to talk about.
Anyway, I hope this all helps!
Btw, how did your girlfriend catch him on these sites? Have you seen him doing this personally? (is it possible that she mistook what she saw?)
