Most Helpful Guy
It's either one of three things:
1) he has had a bad experience with relationships in the past (abuse/manipulation, fights, cheating, etc.), or has seen relationships be bad with people he interacts with, and is scorned by them
2) he wants to "play the field" and not want to have to be obligated to turn down female pursuits via having a girlfriend
3) [this is VERY rare] he may be moving away from the area shortly, and doesn't want to get anyone emotionally attached to him
Frankly, #1 and #2 are equally feasible options.
Which one do you think he is, QA?