Stick it out or say goodbye?

I currently have a nice boyfriend right now. We have been together for about 3 months and no fights or disagreements. Like I said, he is very nice. However, his personality has seemed to of gotten stranger as time has passed. He literally has no friends. When I went out of town, he went to see a movie by himself. Then, he does odd stuff like working out to the point where he is really sweaty, laid down on the concrete, took a pic of the sweat print & uploaded it on FB. This was the highlight of his weekend I think. Also, I am lucky is he brushes his teeth once a day. He is nearly 27, I shouldn't have to tell him that his yellow teeth are gross. But, I kinda have (in a nice way, I swear). I just don't know what to do. I feel like I want to spend less and less time with him. Are these reasons to break up?
Stick it out or say goodbye?
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