Is that a small step to win a little of myself back again?

2 weeks ago, I crossed my ex and his f--k buddy in a party. Also I managed to be high and cool, said "hi" to him with calm, and didn't look at his partner even once. But still, it was so bitter and toxic.
Today there's a party at the same bar. My friends are there. They called me. I wondered for a while. I wasn't in mood for a party today.
What if I cross him again? I want to see him. But it'll be very bitter. I can show the cool face, but for what? Just for him to think that I'm so over him? While the fact that it is not. Or what if I cross his f--k buddy? I'll ignore her like I don't even notice her existence? It'll be so bitter too. Moreover, I'm not in mood for party, so if I go there, it'll be for him, not for me to enjoy myself.
So I decided to stay home. That is just for myself. Yes, I've managed to do something just  for me, not for him anymore. Even though I feel uncomfortable when he is out there, partying, while I'm home alone. But being home is what I want to do today. 
Is that a small step of the progress of winning myself back again?