I was utterly hopeless after exwh walked out, and while I still scratch my head at WTH happened to my marriage and the father of my children, I can say the dark tunnel DOES come to an end.
For me, it took lots of counseling, tears, self work and reflection...and then one brief (mainly physical) fling with an old high school friend, and I started feeling like life was on the up and up again. The fling was about 9 months after my ex walked out, 5 months after finding out, and 2 years after the marriage was pretty much flailing.
When my ex left, I joined a divorce support group. That is where I met my SO. We were on friend terms for about a year as we both worked on healing and processing our pain. We both had one fling. Then on New Years Eve of this last year, we met up...and that was that. Maybe some would say that's too fast, it's not healthy, we are both on the rebound. I guess I don't see it that way, in that we met literally sharing all of our intimate feelings about loss and pain, and were able to sort of fall in love in reverse, if that makes sense, as we went from that to starting to date and have fun and see the joys of life again, together. While we are only 8 months in, we have so much fun together and such great communication, he has made me realize what I deserve and what I was missing. No matter what happens, I see that as a huge plus.
Be patient...do your self work...don't rush it. Try going online to the Meet Up website (that's how I found the support group.) OLD was a little scary for me, although for some it proves to be worthwhile. Good luck.