Gf (23F) ex sent me (25M) message that changed everything

Me and my gf have been together for three years. We have a good relationship, fun, pretty good sex. We have been planning our future, getting married in two years. We had trips, and I was planning to propose next month. Everything was great until yesterday. I was at my house; one of her exes (I don't know how he got my profile) sent me messages on FB saying how she settled down and she will come back to him. I just opened it and left it there. After thirty minutes later, he sent another message. This time, it was photos and video. The video was, as you guessed, their tape. She was acting different, talking different, doing things she said she didn't like when I tried like being rough, slapping her, calling him daddy. The worst part was she was orgasming a lot and saying a lot of stuff, calling his how big it was, which looked more than above average (I have average). It's how she can't take it and the photo was their text. She was talking to him different, how she can't wait to have sex again, even if it made her sore; it was worth it. Calling him daddy, how she will be crazy if he leaves her and she will give him whatever he wants. Sending him nudes without him asking; he didn't give her that much response in the text. She will beg him to respond, send him like four texts in a row. After watching all that, I just couldn't feel anything. I just sat there, turned off my phone, thinking everything. How our sex was compared to this, how she did everything with him and denied me. How she was praising him, how she said she liked my size, but how she acted in the video just felt like less of a man. After like three hours, she got home from her work. She immediately asked me what is wrong and why I turned my phone off. I just said I was tired and wanted to rest. She knew something was wrong; she asked too many times what happened. I just opened my phone, gave it to her. She got really angry and she started talking badly about her ex, how he treated her bad, and how she will ruin his life. And saying I was the best at everything, better than him, how she disrespected her, cheated on her.... I just kept listening to her. She asked me to say something; I asked her was everything a lie—her being satisfied with my size and sex. She said no, and I asked her why she let him do everything I wanted, but deny me. She was getting angrier. She said she was young and she changed and don't like them anymore, how he made her sore, how I'm a better lover, how I satisfy her more than him, how I treat her good. At that time, I was just repeating what I saw in my head and told her I need time to think. She said more things, how I'm throwing everything away, and she left. After that, I had some drinks and went to bed. In the morning, there were so many missed calls from her and her friends, and voice messages begging me to answer. I just can't see things the same way again. Even if we get back together, I don't think I will ever want sex again.

And if anyone knows medical ways to increase size, pills, surgery, or anything?