I didn't know everyone he knew so it's hard to keep an actual track, but somehow I can tell he has lost several. Not to mention the times people have come and then left not long after like with Junpei.

And yes, maybe contentment is the word for it. Still it makes no sense, he can go with anything and it's not as if he avoids people as far as I know, so how come he's not getting more people? Maybe he has also fallen into habit because Minako is the outgoing one of the two?