Dear friend,
Normally I will not believe any story I read here but replying on the off chance that you are genuine.
You asking a question here means
1. You are desperate and have nobody to share it with
2. You just want to see people react.
If 1. Then listen to some serious advice.
GROW A PAIR OF BALLS.
In a relationship Female is the nurturing while Male is the leader.
If she has given up nurturing that means she no longer respects you to lead. It really doesn't matter what you earn, what you are worth or how much you "LOVE" her. You are DEAD to her. You are a useless babysitter who will nurture her young while She get the Banging she "DESERVES".
You should get a mutual consent divorce ASAP. Record her with her BF. Get a good divorce lawyer. Female will be better as they are less likely to be soft on woman. Before she realises that her BF has been pumping her before dumping get free of her. If they marry all the better.
As far as remaining single and lonely, you have a 12 year old son. You have a ready made best friend waiting for you to wake up and look at him. House work can be done by a maid for cheaper than what your wife is charging you in terms of uncertainty and mental pain.
And if you still seek female companionship and really want relationship…
Improve your self. I guess you are in late 30 early 40. Groom your personality, exercise and gain confidence that you have lost. Be an Alpha.
If you truly get rid of that leech now and work on your self, here is my prediction.
3 years from now that BF will start aging and stop having any attraction to the banged up cooch. Right now it is your crying that is keeping him interested. The moment she is free from you she will latch on him and he will start to separate from her. She will then get banged by everyone and everything with a dick. When you improve and at 40 she starts to fade she will suddenly remember that she is a loving mother and great wife. She will then try to use your kids to get you. DNA test your younger child and then become best friend with your older son. You will attract good women like flies to hot Jalebi.
As far as today is concerned - chin up and one step at a time.