Almost-requited crush - how to cope?

Hi all,

I'm hoping for some coping strategies to deal with a recent upset. For the past 3 years, I've had a crush on a regular at my local gym. For the most part, we didn't talk much, but I'd see him in passing and I would get butterflies when I saw him. For the first 2 years, I dismissed it as shallow and stupid.

I don't date as a rule - I have been abused and taken advantage of by men in the past, and I rarely experience attraction. He's the first crush I've had since I met my last boyfriend 10 years ago, who strung me along for 2 years while seeing 3 other women.

Over the past year, I started to make efforts to get to know him. At first I could not even bring myself to walk past him and would avoid him purposefully because the feelings I would experience were too overwhelming. But gradually since last summer I coached myself to start making eye contact, smiling, saying hi - all the little things. I watched his reactions to make sure he wasn't uncomfortable, and he seemed to like me. Over time, we developed a good rapport and I was no longer uncomfortable. He was sweet and helpful and I began to get really think I could try and make it work. I admit I got a little hyperfixated. I thought about him all the time, imagining what I might like to say to him, making plans on how I might ask him out. But between repeated UK lockdowns and my own shyness, I could never quite find the right moment. I tried a few times, but the conversation got away from me, or it never felt like the right time.

Last week I finally asked him out. He immediately said yes and asked for my number. I gave it, absolutely beside myself, and he told me repeatedly how flattered he was and how brave he thought I was to approach him. Giddy and ecstatic, I went home and waited for him to call.

I waited a week. Nothing.

Then at the weekend, he came up to me and explained that he hadn't called because he had just started seeing someone else and thought it would be unfair on both of us if he started seeing me, too. He has gracious and apologetic and asked if we could still be friends. I can't fault him for that.

I am honestly devastated. I can't stop crying. It took so much for me to get to this stage, and to find out that I had a chance but missed my window is just destroying me. I'd rather he just gave me a flat "not interested". I know I am not entitled to a chance with him - or anyone! -  but I'm furious at the world how unfair it all is, and myself for not asking sooner. Part of me wants to cling to what little hope I have that he might stop seeing this other girl, but I'm also afraid that I will end up stuck, clinging to the possibility forever. I also tend to blurt out stupid things when I get emotional. I don't want to sound desperate, or make him uncomfortable.

What should I do? I don't want to leave my gym, but I cant tell how I will react if I see him again, and I'm not sure if I'm ready to give up all hope just yet. It doesn't help that he's just been so nice about everything. It makes me feel like I missed out all the more. I'm feeling everything so intensely and I just want it to stop.