Straight happily married man of 20 years. Because of this I kept a distance from most personal relationships with women especially at work. However, i've had 4 friendships with men that had some sexual tension...even if I wasn't aware of it at the time. Don't know if it counts but I'll share.
Friend 1) He was a great guy. Just an amazing personality, he was dating a nice girl and was a friend of my young family. He was even there for the birth of my first child. Genuinely a kind person, fit, attractive and just ...man I miss him. However, this was the early 2000's. I had only been married a year and I was 19 myself. We were still kids. When he came out to me as we had a couple drinks on the porch with my wife and baby inside...I freaked out. I made it about me, about my feelings..about betrayal. I was to ignorant at the time to understand that he was really putting his whole self out there for me cause he trusted me and I did the worst thing possible. I crushed him. He moved after that night. We never spoke again. I wish I could find him and apologize but that's just being selfish again... I don't deserve to be forgiven for how I reacted. I'm sorry.
Friend 2) A few years later I was a security guard over night and met the funniest guy. We would patrol the a retail area together after hours and basically laugh the entire night. Super cool guy. Well spoken and an intellectual, I always thought he was straight as well but in retrospect we never talked about women. I quit that job and the next night at 2am got a text that he missed me. I called him and was like hey I think you got the wrong number and he drunkenly confessed "no i texted the right number, I felt something between us and I just wanted to see if it was mutual, always wanted to kiss you, electricity in the air... etc etc". I learned from my previous experience, told him look i'm flattered but I'm happily married and he hung up and we never spoke again.
Friend 3) He was a nurse at my office in my mid 20's. I would go to him when I felt ill for some over the counter stuff. One visit we got to talking and the conversation got like really deep. He started telling me about how he was married to a woman but then realized he had feelings for guys and switched teams. It was cool that we could be so open. He would hang out with my wife and I and our friendship was one of the best of my lifetime. One night he asked me to go dancing with him on his birthday..my wife being so cool was like go. We danced and drank and eventually ended up on a smoking patio. He told me he had some deep feelings for me and I shared the sentiment. But I told him the feelings I had for him were not sexual...I loved him for the person he was but that was it. He asked if he could have a birthday kiss and I gave him a peck and we laughed. He said "I would never do anything to disrespect you or your wife" and I told him I knew. Cause he was that kind of person. Everyone loved him. He eventually found love, they adopted a trio of orphans...he was full of life and was finally sharing it with someone. Cancer was found a month after their adoption. He passed two months later. Everyday I think about the simple peck on his birthday and how much it meant to us...even if it was just a little spark, I'll carry it forever.
Friend 4) I'm now in my mid 30's. I realize that even though i'm not gay I am a genuinely passionate and open minded person. That seems to attract gay men so I just try to be aware of that and have made peace with it. I have an office friend and we have sexual tension at work. This time I decided to address head on and we make light of it..joke about it and even some light hearted flirting at times. He respects my situation and the joking never goes out of line. I learned form my past experiences that the best friendships are the open ones and feelings are feelings. It's actions that matter and if you address the feelings before actions are had you can salvage a powerful friendship. Also alcohol tends to be a common factor in all 4 of my stories. I told my current friend to never give tequila so now everyday at work he offers me tequila LMAO.
(Also, yes my wife knows all 4 of these stories...she trusts me and knows I only drink tequila with her.)