IMO it's fairly clear that Mary has done her best to train her husband to stay away from her with her bad moods and complaining. It's an interesting theory that Anne's "Cinderella curse" would have followed her into marriage, but we are told that she gets on well with her BIL even though she turned him down. I think he would have much less reason to avoid his wife if he were married to Anne rather than Mary, and we are told that both Lady Russell and Anne feel that he would have become a better person if he had married Anne instead of Mary, so he might have learned to be even more attentive!