resurfacing feelings, any advice?

my first relationship that was serious was a little over five years ago. we were both 15, dated for almost a year. he immediately moved on after our breakup, I took a lil time but found new people throughout high school and so forth.

i always thought about him tho and how he was doing throughout the years.

flash forward to today, im in an open relationship with people who are great to me and fully support me. yet a couple of days ago i started having dreams about my first love and haven’t stopped thinking about him since. it feels like i’m still mourning the relationship. i crave talking to him and i wonder what he is up to all the time now. i’m feeling stuck like idk what to do :/ i know he still resents me for the way our relationship ended because i did try to reach out and was ignored so now i’m just feeling shitty about the whole situation overall. :(