Why did my ex jump so fast?

My ex and I dated maybe 4 months. We broke up 3 weeks ago and he was on dating apps about two days after. I’m still on them. Does this mean he be as no respect for our relationship? That he lied about how much he loved me? I would find it difficult getting on a dating site right now or even talking or dating someone new at the moment. I always thought after a break up a person should fix themselves... not jump to someone new so soon.
Why did my ex jump so fast?
Add Opinion