You are not alone in the real world or here, but what you are going thru and feeling right now is perfectly normal. We feel rejected, unloved and let's face it, like a toy that has been tossed aside and forgotten. All of these feelings are very normal when a spouse goes off the wagon and hits the trail for something "new". It's truly not about you at all but about the mlcer. He would have done this no matter what and he could have been married to someone else, a priest, minister, hobo, etc., he would still have done this. It truly isn't about you at all, but about him.
Right now, you are trying to fill a void of validation and wanting to be loved, etc., but doing so by self medicating with sex is not the way to do it. First off, in this day and age of STD's, you have to be careful who you do the "deed" with, second, you don't want to end up in a string of casual relationships that basically fill the void for a period of time and then rejection and emptiness come around again and again, the cycle begins once again.
You are far more precious and worthy of someone's true love and that has to start w/friendship and work up from there. You both need to learn about each other, share things w/each other and if the man is truly worthy of your love, he will understand that things have to go slowly and will respect you for your decisions. The right man will come along when you least expect it.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.