Sion has no problem with the idea of getting married! He just resents having it pushed on him and takes huge issue with the idea of just sleeping around with random women. Basically his issues in canon are twofold: first, a reluctance/fear of getting close to people less they be killed by someone trying to hurt him, and second, a deep disgust and hatred of his father, who DID do things like kidnap and rape random women, and a desire to be nothing like that. His experience with Canis in Sabra helped enormously on the first issue, though he still has some hangups on the second. Though it's possible that someone like Tazendra or Arianna could convince him that no, if both parties are okay with it then it's not necessarily a bad thing, if you're careful and take precautions... (And Arianna may possibly wall him a bit anyway if she visits, so. :|a)

But basically what that means is that he's still not likely to go sleeping around, but if/when he found someone he either really liked or felt he COULD come to love, he'd probably have no problems with the idea of getting married. He just wants it to be on his terms and not someone else's. :/

So someone needs to find a way for Tazendra and Masamune to meet post Sabra y/y?