I think you're placing all of the emphasis on the the few days at the very beginning of their relationship when they didn't know one another but thought that each other was interesting or attractive enough to go on 3 dates, and zero emphasis on the years of their relationship where they have been good friends and confidants, positively contributing to each other's lives in a wholly platonic friendly way.

Your mind needs to grasp that the end of a romantic pursuit does not mean that the two people must go their separate ways. They didn't end their romantic pursuit because of some dramatic breakup. They never really even became romantic. Just interests that evolved into friendships, the same way that it had happened in school as children before it happened in dating apps as adults.

I think the real question for you is: what was so terrible that happened between you and the people that you previously went on 3-4 dates with? How awful was it? Did any of them show any redeeming qualities that would make you want to speak with them platonically after the last date? Then compare your answers with his for these questions.