I met a female friend of my BF for the first time last weekend. She was with her male friend and we spent a couple of hours in their company. As we left and when my BF was out of earshot, she caught my attention and said "be careful" twice. I nodded but now I'm in a quandry about what to do next. We've been together 5 months and he seems a gentle man and we get on well. I feel like I should press for more information as this is some kind of mysterious cryptic message if I don't. I've started to imagine what demons are in his cupboard.