All of this talk on letting them go...

[Ihavehope]

Long story short: together 6 years, married almost 4, three kids (2 are his step). ILYB dropped august 8th, with no back and forth or regrets or doubts since that day. Affair likely, but not confirmed, but at this point nothing I can do about it. I'm not big on the exposure, at least not for me, and the few people I have exposed to (his mom) chose to believe him, anyway, despite evidence I have, because other than catching them in bed he will deny everything I can come up with. He now lives elsewhere, and we are separated but not legally. 

Ok, so, I have a question about letting them go:

WH is gone, with an unconfirmed affair (I believe it to be happening, he denies, I have no other proof and have decided to let it go at this point because, honestly, I will likely never know the full truth). 

He is still of the 'i do not want to be with you in a relationship' mindset. But he wants to be 'friends'. By friends, he wants to hang out comfortably for an hour here and there when we exchange kids, talk once or twice a day about little things, and hang out occasionally. 

Part of my problem is I was receiving what I perceive as mixed messages, but in general I know he doesn't always understand how what he says and how he says things confuse me, so I try to remember he's not giving me mixed messages, it's my want to see doubt and hope that makes them mixed (for example, he has told me he still feels a connection with me, above the natural connection of having a child together, he says he cannot 100% guarantee we can't be more than friends in the future, and some other little things here and there)

So here is my dilemma. Can I let him go and still be 'friends'? He still says I am his best friend, and would do anything for me (except save our marriage, of course). He is used to people leaving him. He does something that makes someone mad and they walk. And he let's them. Past friends, girlfriends, even his mother cut him off for 5 years (for a really stupid reason, but he gets his stubbornness from her) and he let's them go. It's his coping mechanism. He is, for sure, a runner. He runs and avoids problems until he can't take it, and then you get the ILYB bomb. He is still running from minor issues now, telling both me and himself 'it will get better when (insert some future thing that he truly believes will help)'. He is completely nonconfrontational by nature, and if I do ever rant or get mad he listens but doesn't engage. Never has. 

In order to let him go, mentally, I think I can do that and maintain a not really friends but friends approach. But, I'm not there yet and wonder if I'm sabotaging any hope I may have. 

I know that when you DB you do go for an attempt at reconnection through friendship, but most of the time that comes after a period that the WAS misses the LBS. This also applies to couples who fight all the time, and are attempting to stop that. We don't fight. We never really have. I'm not trying to escape arguments or fights or uncomfortableness (though he IS trying to escape that last one). So... What do I do? I don't even know how to do the 'stop what doesn't work and try something new' because i can't tell if this is working in any real capacity.  This next week will be the very first time we will hang out without kids since the bomb. He sees it as a way to be friends. I want to see it as a way to reconnect. For a lot of couples here this would be seen as a positive step, as working, as something they want, but because i know he's going into it as 'this is what friends do' its not a clear cut 'this is working' sign.  

So I'm  so very lost on what to do. If he wants to divorce me, i will no longer try to stop him (we have decided to wait until after the first of the year for tax/school purposes). But I don't want to think I'm still doing everything wrong and regret it later. 

Help?