I recently discovered that my (33F) boyfriend (36M) of 1 year had been cheating on me with at least one other woman for months. I am sure there were more hook-ups or/and more women he tried to sleep with. I had often discussed cheating and fidelity with him during this period, and he always said that it would be a "cold day in hell" before he cheats on me, etc. He had several opportunities to come clean but did not. This woman wrote to me a week ago. When confronted, my boyfriend denied everything. It was only when she sent evidence, that he reluctantly admitted to "moments of weakness". I am stunned at the cold, calculated way in which he tried to deceive me. He told her that I would never find out and to just keep all this to herself. Also about how cheating is HOT and nothing else matters. He was trying to meet up with her even 2 days before I found out. I am in a state of shock. After a confrontation, I blocked him everywhere. He is still swearing his unconditional love for me ("you're my entire world") on email and is acting contrite. By way of explanation, he said that he had lost all discipline from his life, was grieving, and could not control his urges. I just cannot square who he was to me with the person in the screenshots of chats the woman sent me. The subterfuge is mindboggling. The most hurtful part is that he also tried to hook up with her a day after meeting my family in my hometown.
So, I guess my question is — Does he seem to have any guilt for what he did? Why does he want me back so desperately? Why did he talk me into a monongamous relationship if all he wanted to do was sleep around?
He has also had unprotected sex with her and now I am getting tested for STDs.
TL;DR: boyfriend of one year cheated shamelessly; desperately wants me back now.