I (30F) have a friend (26M) I've known for 5 years, who I recently developed feelings for. He was in a monogamous relationship for 4 of those years, and while I had a crush on him, I did not see him as someone to date out of respect for his mono relationship. A few months after his relationship broke down last year, he began casually dating after having a conversation with me about ENM. Mind you his take on everything seemed to be casual dating = casual sex (no feelings in case of assumed escalation).

I spent ages thinking about whether or not to ask him out, as I did not it to negatively impact our friendship if he didn't feel the same way, and as we are also work colleagues, I didn't want to make things awkward at work. I eventually thought I might as well take the shot and see what happens - maybe it would lead to something great. He accepted and we discovered we had shared feelings.

He had also asked out another new colleague around this time, but as she was freshly out of a long term relationship he was concerned it would be a rebound.

A couple of weeks later, we ended up sleeping together, though he did make me aware that he was also still actively persuing the other person still and things were going well, which was fine with me since I'm ENM minded. I went into it with the understanding we were exploring as friends and that it would be an ongoing, healthy thing. We had had a discussion confirming this in order to determine expectations and boundaries, and since he had feelings for me, too, I certainly trusted him to be telling the truth.

Things have since escalated quickly with the other person and he said he wasn't comfortable seeing me still as he felt he was emotionally cheating. I'm unsure at this point if it's emotional immaturity, or he's blinded by NRE, but his actions since have not lined up with his continued reassurance that he wants to maintain our friendship. He hasn't reached out once to check on me, even just as a friend, and things feel super awkward at work. He has been happily telling everyone he is now in a relationship with this other colleague, and of course they are all happy for him. Because we agreed not to tell everyone we were dating at the time, I feel super isolated hearing and seeing this happen.

I guess I'm wondering if anyone has been in a similar situation before, and if the friendship was salvageable? I'd hate to see a great, 5 year friendship thrown away because of NRE, but I'm not sure what else to do. I feel anxious and depressed about the whole thing, but I do recognise it's a situation I put myself in. Just looking for advice from fellow ENM minded folks.