How do I not act a fool?

[6feetunder]

I have a former TA who gave me a B- in my overall grade last semester, putting my scholarship into jeopardy dating a former classmate of mine. We all work at the same place.

They've been talking a lot for the past few months and today I see them holding hands. The TA guy treats me like I'm invisible. He talks to me rudely like I'm his younger brother. Growing up the youngest in my family I left home for school in order to be my own independent self and I get this guy here. He has close ties to the superiors in the place I work and I feel like telling him to treat me with more respect or I also feel like just giving him the silent treatment no matter what, even at times when we'd usually pass each other just saying hi.

How do I not act a fool, maintain my work integrity, not cross my bosses with this punk, and also not let my feelings get hurt by this jerk? (I have no crush on the girl he's dating out of desperation, I'm seeing other women).
We all three played tennis and I told him before, numerous times, to let me know when we can all play again and I found out they've been playing without me.