I feel like I’ve been doing a lot of this lately, but the answer to your question is yes and no. Let me explain:

First of all, yes, not only can you two remain connected, it is infinitely healthier to exit a relationship with a sense of “well, this just didn’t work out” rather than “this person is an idiot, a fake and a liar.” After all, you were with Dave for a relatively substantial period of time and casting all of that time aside with personal attacks isn’t going to do anyone any good.

Second of all, not in your wildest dreams. The reality of the situation is that you two were intimate for years on end… years. Not only were you two naked together, you undoubtedly challenged each other in the way that couples do, forcing some tough introspection and leading to some gnarly disagreements. Those issues don’t just disappear – he will see your character flaws as a friend, just as he saw your character flaws as a lover. You too, you will see his problems just as you did before.

You just can’t go back from that. If and when you move onto a new partner, every time you hang out with Dave, the potential for things to get either A) sexual or B) a little too snippy for “just friends” is just too high. Your new boyfriend would (and should) feel uncomfortable with that situation.

So what should you do? It’s eminently healthy to check up on Dave, maybe even grab a cup of coffee with him from time to time. Tell him how you are doing, see how he is doing – that’s all fine. But your meetings should not last longer than about an hour and you should not see each other with any sort of regularity.