This happened to me, and the other post the PP was referring to could well have been mine.
Difference is I am married, he was single.
Not sure how he felt about me, but he was always respectful of my situation and platonic boundaries, was friendly with DH too and whatever the case I would never ever have gone there, as I have a happy life with a lovely husband and obviously it's morally wrong.
It all peaked a couple of months ago for me after he started putting a kiss on texts- i accientally did it once then he did it back having never done so before- which I guess made me wonder if there was something more on his side.That was around the time I wrote the post pn here, then I just kept thinking about him for awhile often, which i felt very guilty about, but it has really faded off recently.I don't see or contact him much anymore which probably helps things, as our kids friendship has fizzled out quite abit, and we don't collect on the same days so never see him at school.
I think i just liked the buzz of someone who i found attractive giving me attention...could that be the same for you? I think as mums we can often forget about still being ourselves too, not just a mum, so it's exciting and a confidence boost to feel like someone fanciable might have a crush on you back, even if you know you'd never take it further.
And i guess that would be even more so for someone who is single and available.
I appreciate it must feel harder as you aren't in a relationship,but give it time, pull back abit, and like my situation I'm sure it will pass for you too.
If you meet up with him for playdates etc, maybe see if the wife can come too and you may become friendly which might help you get over it.That's what I did with getting my DH to join in the playdates...made it much easier to suppress any feelings as it wasn't just 1-1