I knew it was over when he wouldn't give the other woman up to save his family. Short story- my ex and I were together 5 years, had a son together and were engaged to be married in February 2011. We set our wedding for December 2012. Two months before our wedding, he lands a great job in Philly, paying close to six figures. Unfortunately I was finishing a bachelors and I couldn't move right there with him. So we planned to live apart until I was done with school (I only had 1.5 semesters to go).
I guess the money and freedom got to his head because he met a second year med student shortly after moving and started sleeping with her. I still don't know if he slept with her before we got married but two weeks after our wedding, I went through his phone and found out when I read all the text messages. Lots of details so I will skip to the point.... I signed up for an infidelity board to figure out what to do. In the meanwhile, my ex did all the standard wayward behaviors because he was caught. I knew when it was over when he didn't seem to care for his family any more- he just wanted his med student. He actually called her a hot sexy angel while he was talking to someone else, citing it as his reason for continuing with her.
The infidelity board taught me way more than I even imagined. Infidelity is synonymous with someone on drugs. There is a "high" that someone cheating gets (endorphins) and that is why they keep doing it. Most cheaters blame the person they are with to deflect and avoid responsibility. When someone cheats on you, IN ORDER TO NIP IT IN THE BUD, you must leave. Cheaters fantasies are popped when reality is introduced. So on and so forth. It isn't an experience I wish on anyone, however I am glad I learned it. I now know about healthy boundaries, red flags, and what to actually do if I encounter infidelity again. I semi feel like I have a PhD in Infidelity due to the amount of reading I have done on the topic. It is insane.