I actually have never thought WL was the issue. More, I thought that RS had heard something about OP's behaviour that had upset her and she may have brought the subject up over dinner on the 13th. Sadly, as I have said earlier, I think RS (though a loving and kind person) was in love with love and was quite naive in this respect. I tend to think at 30 one probably should have enough experience to know the difference between infatuation (which can so often make allowances for poor behaviour from a partner) and a truly deep and abiding love with mutual respect. Perhaps the relationship was too young and she too eager. It is so sad that her young life was ended by someone who appears to have a lifestyle and temper that we are likely to hear a lot more of during the trial.
Earlier, on here, personality disorders were mentioned and I tend to agree he suffers from some such affliction. Borderline personality disorder seems to slot in nicely with his behaviour though I think the newer European definition is perhaps more appropriate.
http://www.bpdworld.org/what-is-bpd/diagnostic-criteria