As
@Sylvia said, Mervin already has his Green Card, and he's well into that whole citizenship process. Since he'd invested a lot of time, money, and effort into the process, surely he saw no reason to ditch the process of working toward U.S. citizenship at the 11th hour. In any case, it's possible for Mervin to retain his Canadian citizenship, when he becomes a U.S. citizen. And he likely enjoys skating for the U.S., having done so for awhile now. The other part of this, which I already mentioned is that Mervin and his former partner, Marissa Castelli, had expected to stay together for the remainder of their skating careers.They were committed to making their partnership work, but it just never got a good start out of the gate, and sadly began limping before the first turn, eh.
M&M were good together and they had great potential, despite the problems they faced. They went as far as they deemed they were able to go, and then it was over. Mervin wanted to keep skating and so he found another partner. And I hope he sticks it out with Serafini, and that they improve and have fun together. You can call Mervin whatever you wish, but he's a damn good skater and a skilled pairs partner, one of the best! He's also cool, witty, and a decent guy all around.
He won the 2012 Worlds bronze medal with Japan's Narumi Takahashi, because they were a very good team on the rise. They'd worked hard for five years to reach that high point. It wasn't Mervin's fault they ended up splitting. He and Narumi will always have that bronze medal victory and those triumphant moments.