Not saying it's not her fault, but do you always deserve the things you impose to yourself? Do self-loathing character deserve the suffering they impose on themselves? Most of the times, it's kind of unfair.. Although, I can understand the general incomprehension or disdain.
Otherwise, I agree completely that she is imposing it on herself, but what to do when your life goals clash with your love life...
That is indeed her dilemma. How to solve it. Make a choice and hurting some people and losing a part of her future she would like, living with Yuzu and ruling the school on her own terms.
Or, a Deus ex machina could help her to find a third path. But i doubt it, all the manga's message, trough Shou and Yuzu, is to follow your own path without any regret. Is it really her gold life? Maybe Mei will have to reconsider it and wonder if she wasn't mistaken in believing it was what she wanted. After all, when she was ill, she almost told Yuzu she didn't really like all these responsibilities.
Anyway, i conflicted on the solution the author will give, something evident like Shou coming back or a real surprise with something unexpected.
The only thing that I could see happening, other than Shou coming back, would be a super cheesy scene with Yuzu and all the girls storming the wedding and objecting, assuring gramps that all of their (powerful?) families will keep supporting Mei in the future, or some other power of friendship crap like that.