Romantic relationship discord sure can bring out the worst in all of us. It triggers primal attachment issues and we can react infantile. Someone can be the most professional at their job and then act immature in the love department. I think it’s the strong desire to want to be loved, and find the person who is the right fit. That desire is so strong that we decompose in disappointment when it becomes apparent this is not the case with that person. It’s rejection and disappointment that triggers.

You jumped all in with intimacy very fast with him. There’s no law against this, obviously, but it’s really not the best way to approach relationships. It would have been better to build the relationship first. You might have enjoyed doing those activities with him that you have in common while you got to know him better. You would have seen that he didn’t want a commitment, and you wouldn’t have invested in him romantically because you weren’t intimate. You’d be just friends who like to do sports together. Maybe next time take things slower?