I (28F) have a friend (31M) who we've been friends with for over 15 years. We've always flirted when we were teenagers and I've even had a crush on him for a long time. However we lived in different countries so we never ended up trying a relationship. He constantly expressed how he thought I was a great girl and any guy would be lucky to date me.

However, when the opportunity did finally arise for us to spend a significant amount of time together 3 years ago (I was visiting his country again), we ended up kissing and having a very romantic time but when I brought the "so where is this going" conversation he was uncomfortable. I know he said he "hated long distance relationships" but his coldness after we had kissed very passionately (it was clear he was also trying to get it to lead to sex, which I stopped) really put me off. He was very "casual" and wouldn't really answer my questions about what was going on between us. This actually made me extremely sad at the time and I realized that someone who truly was right for me wouldn't put me in such emotional distress.

A few months later I met my now-fiancé and we are extremely happy together. He's the perfect guy for me. This male friend (described above) has been reaching out because he wants to "talk" on the phone and since we hadn't talked in a while, he doesn't know that we are engaged. He's still single as far as I know. Often when he we talked prior to me dating my then-boyfriend/now fiancé, he would be very flirty etc.

Since we've been friends for 15+ years (at least before the weird way he behaved after we had made out 3 years years ago) I don't want to cut him off completely. But since he seems very adamant about us "talking" (in a very hopeful/solemn manner), how do I break it to him that I'm engaged and he has missed the boat? I also feel uncomfortable with talking to him because the last time we talked was almost 2 years ago when I was in the early stages of dating my now-fiancé, and he was still weirdly flirty despite having refused to pursue anything with me.