In time you will both realize the value of spending time away from people who don't want to spend time with you. It was a hard lesson for me as well. This is the first (after 3 years) NYE that I haven't spent the night in tears and pretty much alone. Tonight I am going out to celebrate with some friends at a party for 1000!! It has taken me this long to "want" to move on and start a new life for myself after many years of wallowing in the fact that he is with some other woman and I am alone.
The reality is........they are where they belong at this point.....with another cheater and liar. They may act happy but that doesn't make a happy person inside. Inside they wallow in the guilt and anger they hold inside. Eventually karma will happen. I have to believe that. It is what has helped me to make it this far.
Irene.....don't mistake being alone for being lonely. Go rent a movie and call up some old friends or family that you haven't talked to in ages. Cry and scream if you have to. Tomorrow will be a new day and you don't have to deal with this for another year! Don't hurt yourself further by spending time with your ex unless he wants to spend the NYE with you. It will just lead to you hurting more.
I feel for you both since I have been there

Just know it can and will get better each year.
I am thinking of you both.
Kid