I ran into an ex and had this moment where I find out they're doing better than me in life.
Why would you bother yourself with an ex?
I want to see the reactions of people after not seeing them for a long time. Unfortunately, this turned out making me feel worse.
It's nice that you ran into them, but you didn't have to stay and listen. Your health matters and your ex brings you back to a dark place. Next time just walk on ahead and fully stop involving yourself with them.
That's a good idea.
And remember that not all things are what they seem at the surface. There is a chance that things aren't going well for them either. Sometimes people only bring up the good things about there lives to avoid talking about the bad.