Friend zone

If a dating relation evolves into a platonic non-sexual union, it is sometimes termed the friend zone:

When a guy agrees to be friends, he's forced to stifle his attraction while regularly seeing and talking to the woman he's attracted to. She discusses her love life and has the audacity to ask his advice on it. He performs occasional "manly" household and automotive favors for the woman. Essentially, he does everything a boyfriend would do--without the benefits.

—Gina B