DH (married 20 years) has recently become good friends with female colleague. She is separated with a young DD. Met her at a social event last month, she seems nice and has asked to meet up just with me too. However she messages my Dh nearly every other day now. Sometimes work stuff but usually sharing links to stuff they are interested in etc. I think it’s just friendly and she’s done the same with me (to a much, much lesser extent as we don’t really know each other yet). They do share a lift occasionally too. AIBU to be worried about all this? Dh says she’s just a person and I have absolutely nothing to worry about. They are talking about going for a drink at some point but I feel a bit uneasy about this. Should I invite myself along too or is that weird?!