That reveal was underwhelming...
So much for "I will take you to to top of the world, only to have you plummet to the depths of hell" (paraphrased).
The guy was never dependent on Mia for it to be satisfying when he was betrayed, or at least it wasn't portrayed as such in the anime. They were living their own separate lives, with only the fact that he loves Mia, and that he thinks Mia is also head over heals for him (???) being clear.
Disappointing.