I feel awkward around my partners best friend.

I am so sorry for the long post, this is more like therapy for me. I'll insert a short summary at the bottom -

I (19F) and my partner (19M) have been together for over a year. Before we started dating I was talking to a different boy (19M). I quickly realized I really liked him. However, he nonchalantly said that he wasn't looking for a relationship at the time. We would flirt back and forth and at times would have great conversations, but he would also be hot and cold and leave me on delivered for several hours. In the end, this relationship turned into nothing but friends/acquaintances.

I should note that we live in a small town so most everyone in our previous senior class knew each other. While I was in the "talking stage" with this boy still, my now boyfriend started messaging me as we hadn't talked before but knew we had previously gone to high school with each other. My now boyfriend and this boy knew each other and had been friends previously but weren't super close anymore.

The first boy had made me feel confused and sad, as I could never know what he was thinking or if he liked me. My boyfriend was clear in his signals, took time to message me even at work, and made me feel special. He asked me on a date and didn't confuse me or send mixed signals.

As me and him started dating, these two boys (aka my current boyfriend and the boy I used to like) started becoming close friends again. Speed up to today and both of them are now close buddies. As a result, I see him once in awhile and my boyfriend will talk about him. As you can probably guess, this is taking me time to get used to.

The boy I liked is a really good guy at the end of the day, so I am glad my boyfriend and him reconnected. However, I feel awkward when I see him or hear about him, and when I hear about his current girlfriend it makes me uncomfortable. I can't seem to let go of the childish idea of "why did he pursue a relationship with her and not me?" all the while I am in a relationship, and we had our talking stage a year ago.

Let me make it clear breaking up with my boyfriend is not an option. I am so in love with him and we have a place together, and I plan to get married in the nearish future.

I feel like a douche for still feeling awkward around this man. Is it ever not awkward around someone you once had feelings for? Why does my head still wonder what we could've been? I should note that my brain tends to fixate on things until it's bugging the crap out of me, so I have been overthinking this for weeks. Am I overthinking a situation anyone would find awkward? Please be kind to me as I haven't done anything wrong, I just can't seem to get out of my head about this.

Short summary - I had feelings for my boyfriends best friend in the past, and I still feel awkward, jealous, and uncomfortable around him.