mossflower; As I have stated before, I don't know your situation, and I am no "Dear Abby", but I think true happiness needs to come from within. No ONE can make you happy. They can fulfill you and make life better, if you are already happy.
I realize I have only seen a portion of what you have posted, and that isn't the entire story, but yes, you need to find some friends that you can actually be friends with, and go out. Don't go out looking for a permanent relationship, when you get back into the "dating scene", if that is what you end up doing. Go out as friends, and enhjoy their company, and let them enjoy yours. If you are happy, with who you are, it will be good for both of you. If you are not happy with who you are, no one will enjoy that time. And only you can become happy with yourself. It might mean that you change something about you, or it might be a "simple" change in your way of thinking.
If we are content in our own skin, and happy with who we are, life happens, if we let it. And living, IMO, is the best thing you can do for your girls. They need to see happy and good, as it sounds like they have seen the tension. That living, may occur with your current wife. She may see a neat and fun you, and decide that she doesn't want to lose that. But if she still decides to move on, the rest of your life will help you balance that, and cope with it.
I'd be willing to bet, your wife has conflicts of her own, right now. Both of you being in less than good moods, will not endear either of you to the other, if that is all that you see. Put a smile on your face, even if you have to fake it. After a while, it will become second nature.
My :2cents:, and it might not be worth that.