I read your other thread, and was one of the, thats not too bad.
Put the two together, and I think you need to be asking some questions. It makes you uncomfortable / uneasy / insecure, so DH needs to respect that. However that might mean he stops telling you things. Would you be more upset if you discovered later he knew something and hadn't told you?
In the interests of full disclosure, I regularly have lunch with blokes at work, 'cause there are very, very few women. So its go for lunch with a bloke, or have a sarnie from home at my desk.
One of those mates sometimes comes to visit me at home when DH is travelling away - as in DH is away for the week, so mate picks up a takeaway, and keeps me company one evening while the kids sleep. DH knowns about this, and doesn't have a problem. A female friend does similar when her shifts line up with DH's travels. I probably have a skewed perception of what is normal due to the gender bias in my work environment.
Whatever the rest of us think, you need to let DH know how uneasy all this makes you.