If you find yourself thinking about this too much, you can also try thought stopping techniques found in this excellent guidebook that is widely acclaimed by professionals and written by mental health professionals, concise and very easy to read and effective.
I wish you the courage to persevere and to ignore your former partner and his new friend(s).
I shall keep you in my prayers.
Elliott, MAE, LPCC, NCC, CCMHC
Thank you so much for your advise god bless you and once more thank you from the bottom of my heart thank you