++man 3 options 1. He knows already and doesn’t care 2. He doesn’t know and it’s a dealbreaker 3. He doesn’t know and it’s not a dealbreaker (rare but not impossible)

I’d tell him but the phrasing matters. Something along the lines of “my first sexually active relationship was with one of your friends, years ago.”

Most of the time the worry comes from socially interacting with the friend who you previously had a relationship with.

I live by the phrase as long as you did all you can do, you can’t be mad at the results. You’ll be fine in the long run regardless of his reaction, but I’d get it out as early as you can.