how do i feel closure with my ex?

vv

first of all (let’s call him my situationship since we weren’t really in a relationship), anyways we were really good friends in high school and had a little thing for each other. we tried it out multiple times but it couldn’t work out for some reason. flash forward to maybe three years later, i started working with him for a couple of days out of the week. it’s kind of hard seeing him because i just think of everything that we’ve been through. we basically tried it out again a year or so ago but i ghosted him. recently he got a new gf and that new gf is my FRIEND. yeah you heard it right, my FRIEND. i only met her a month ago but we clicked instantly and when she told me her bf was my past situationship i was kind of relief that he finally found someone good for him. but ever since i started the job i’ve been seeing him more, we’ve been hanging out during our break time since idk anybody there. the feeling of being attached to him is still kind of there hanging by a thread. i feel like since i didn’t tell him how i felt and why i just ghosted him out of no where, there’s this burden inside of me. i feel like i need to talk to him just because I myself need closure to not feel like this anymore. i don’t want to feel like this towards him, it isn’t fair or healthy for his relationship and it definitely isn’t healthy for me. it’s KILLING me that i am feeling like this. anyways i just need help on how i can get closure from this. obviously i can’t just quit my freshly new job just because he’s there. i want to talk to him without making it awkward and i have no clue how to do that. please someone help a girl out! thank you so much!