Oh man, as my foreposters already said, it would be such a pity losing a beard as great as yours because your wife dislikes it ...having read what BT posted, my thoughts were like "Yeah, I agree, if it makes your wife happy, trim it back or even shave it. But if it's not that shaving would make her happy but just give her a feeling of control (don't over-evaluate what I say, I don't know your wife ) and stop her nagging you, then by all means DON'T do it because it will make it even harder when you decide to try growing again."

That's about it For the rest, what Fred said applies, it could well be that she perceives the beard better after some time. It's sad that in most cases there is no chance to have a rational discussion about stuff like that with one's wife/girlfriend, at least in those cases where it's becoming a problem.