Thlayli…….It always hurts to see the ex with a new person....if you had ever invested your heart into someone else.....
I think that is probably some remnant of our primitive lizard brain....some territorial thing....
A few million years ago...an intruder onto one's "territory" would be killed....
Also, I think it is the shock of it...as it makes the whole thing so much more real....
One time, I vomited in a parking lot, outside of my workplace....when I saw my recent ex holding hands with one of my co-workers, as they left the building....
I got over it pretty quickly, though.....