I also think it's weird. A few months ago, I had the new girlfriend of some guy I rarely talk to add me on FB. It felt awkward - if it was some jealousy thing on her part, I didn't want to *not* accept the request, you know? She'd added a ton of his friends, not just me. She must have realized how little I talk to him because she's defriended me already, lol.

The telephone call from Friend 1's boyfriend is even more bizarre - and her not responding to you after that, huh?? I can see why you'd be reluctant to pursue these friendships any further after that.