My question is why if the rift between XH and BMF came about because of XH talking to BMF's XW, why in the world would BMF try to discourage a R between you and XH? You out of the picture could encourage a R between his XW and your XH. This sounds like the last thing that the BMF would want to do.
Could BMF's XW have sent you the book? Maybe she has more interest in your XH than he does in her. If that is the case she would have a motive to try and keep you two apart. It's possible that XH has been talking about you to her and she's getting insecure.
Just another thought on the subject. Straighten me out if I've got the wrong impression.