I think he's a shy person, certainly an introvert. It's rare that people literally go from being introverted to extroverted. Sure, I can see him giving into passion, but I don't see it becoming overly rough. I don't know why; I just can't see him as that type of lover. Even at his age, and with some experience under his belt, I see him being a bit nervous and asking his lover what s/he likes, to guide his hand, etc.
This, or the sort who is always conscientious of their physical strength and prone towards... care, if not always gentleness, where physical love is involved. I'm married to a Marine and while he isn't a hulking stereotype of a Grunt, he is very physically savvy and combat trained (I'm referring to USMC martial arts, not just, you know, pow-pow guns) - passion is definitely there, but also a long ingrained desire NOT to hurt someone he loves,which leads to a certain unavoidable caution... most of the time.

Sorry if that's TMI, I'm just trying to clarify where I get the impression from.