Caught my fiancé of 4 years cheating. When confronted, she body-shamed me. Now she wants to get back together, and I’m lost.

I am an expat who moved to the US 5 years ago. Since my own family is far away, I became very close to my girlfriend's family. She was 100% my type—both in looks and personality. After 4 years of dating, I proposed to her.

A few weeks ago, her sister called me. She confessed that my fiancé had been cheating on me, but asked me not to tell anyone where I got the information. I couldn't believe it at first. Fighting my own guilt, I checked her phone. I found messages with another guy that were so explicit and heartbreaking I can't even type them out here. It turns out this had been going on for 6 months, and possibly with multiple guys.

For a couple of days, I was in denial and shock. When I finally broke down and confronted her, she panicked. But she quickly turned it around, started screaming at me, called me an idiot, and said she loved me and was offended by the accusation. When I told her I saw the texts, her defense crumbled. I asked her why she did it, and she looked me in the eye and said it wasn't her fault that my dick is small.

I felt completely dead inside. I walked into another room, called her dad, explained that we had a massive conflict, and asked him to pick her up for a while before I said something I’d regret. He came and got her. She left screaming at me, but I remained silent.

I’ve been a wreck for weeks. I had never doubted my size before, but after reading posts on Reddit, I now feel defective. For context, I am 5.7 inches long and 5.2 inches in girth. Is that really that small? I never used to think about this.

Now, she is begging for forgiveness, crying, and saying she loves me and is terrified of losing me. But I can't stop thinking that she was faking everything for years, never actually desired me, and only wants to come back because I am financially stable and well-off.

The worst part is, I still love her. I want to believe her, but I’m terrified she only wants me for my money and not for who I am. I’m writing this purely on emotions and completely lost. Any advice?

TL;DR I M found out my fiancé of 4 years was cheating on me for 6 months. When confronted, she panicked and body-shamed my size (5.7" L 5.2 G). Now she is begging for forgiveness, but I'm devastated, insecure, and worry she only wants me back for my financial stability.