Wow what a prick. I don’t think it sounds like you were reading too much into the messages, for the fact that he was the one messaging you separately and suggesting the rock climbing date.
I can’t remember if you mentioned this but had he previously said he was single? Either way, at least you know that he’s not now!
I would do what
@Blonde123 said and casually mention his wife. That way you’re letting him know that you know, and hopefully he will leave it at that. Same as I said in my previous post, you don’t want things to be awkward at work but that should be enough for him to know he’s been caught out!
Be prepared for some bullshit about “oh I’m married but we’re only together for the kids / we’re going to separate / we’re just not in love anymore”
Men