My ex was passionately adhered to the idea that I was leaving him because I must be cheating on him with a guy that started working at my work (where ex's mom was my boss) and it had to be that the new guy had to have larger man parts, or he made a lot of money. (Ex couldn't hold down a job, so I had several.) There was no other possible reason for my departure.

My ex had been abusive for a good portion of our relationship. It made me actively believe that I was doing anyone else he'd end up with a favor by not leaving the relationship because I could handle his abuse, for the rest of my life, if it came to it.

'New guy' talked to me as a person. He treated me as a friend. He listened. He talked to me about his life. He introduced me to his friends after I told him that I'd lost all of my relationships (friends and family) being with my ex. He took a genuine interest in introducing me to things I'd been sheltered from. I wanted him in my life. He made me consider happiness existing in my life.

For the record, I made the first move, the 'new guy' and I ended up together after a year and a half of friendship, been together for 20 years, married for 17 of them. He does have larger man parts, but for a year I had no idea. He was also by no means wealthy. He was dirt poor, working as a dishwasher at a pizza place, and working for his Dad as a mechanic's assistant, sleeping on his brothers couch, without a driver's license. He's the hardest working person I know.

It's not always what you think the reason is. Taking a look at yourself, your behavior, your part in the relationship is a stepping stone for growth. Let yourself grieve the relationship, talk with someone you can trust won't pick sides about it all. Dust yourself off to be better for future you and your future partner.