i will not see myself as the problem. but this is hurting nonetheless. it was lovely to begin with and it helped me get over the awful betrayal of my now ex h
You aren't the problem and, in the grand scheme of things, neither is he. At a time when your ego was on the floor, he came along and gave it one godalmighty lift. Look at it for what it was; it got you through the winter and helped you get over your ex. Job done.
i know i have played my own part
Of course you have. It takes two to tango and you willingly stuck a rose between your teeth because, at a time when you were struggling with being newly single after years of coupledom and all that entails, you needed a diversion. That's why you joined a dating site, isn't it?
I've lost some self respect but it's too late to put it right
It's never too late to regain or re-build self-respect but, in this case, I can't see that you've lost any. Your pride may be a bit dented at having allowed yourself to be swept off your feet and blinded to the truth of what he's about, but no harm has been done to either of you.
You had a good time together - and then you didn't. End of.
that harsh internal voice will do whatever it can to make me blame myself
We've all got one of those voices. On this occasion I suggest that you tell it to shut the fuck up.
he can't face hearing what i've got to say
He doesn't need to hear your dulcet tones gain. All that remans is for you to post his stuff to him with a brief note saying 'Thanks for the memories - have a good life'.
And now let's deal with: Thing is, i began to hear myself asking for more and more reassurance from him that he loves me, really intends to live together etc?and when I did challenge him his response was off
As you were divorced in all but the Absolute and he met you within days of separating from his dw I sincerely hope that, when asking for reassurance that you would 'live together', you were referring to some distant point in the future when his marital affairs were resolved and your younger dc had fled the nest, otherwise the pronouncement of this court is that you were guilty of a desperate desire to enter into another live-in relationship 
Get yourself back to that beach and start skimming more stones before your thoughts start to turn longingly towards your ex. And they will, honey, because if you don't look forward to the future with confidence in your ability to become all that you can be without having a man in your life, it's entirely natural that they'll turn to the past.
Your experiences with everyone you like, love, hate, or are indifferent to, form the rich tapestry of your life. Use them to enrich and empower yourself and don't waste your valuable time on 'if only's'.