Help me with this please.

I am in a relationship for about 6-7 months. She asked me out. She said she liked me. I wasn’t sure at first but decided to give it a try. I was taking it casually at first because i wasn’t sure about her but eventually i developed feelings for her. We had sex. I didn’t make much effort to make her happy all the time. I rarely said that i loved her. But i knew she also lied to me time to time, she lied to me even about very small details, so i wasn’t sure about what else she might be hiding from me, so i broke up with her. But then i realized that i really loved her so i patched it up after 4-5 days. The day after we patched up i checked her phone and found out that she sent her nudes to some other dude. She sent those the day after we broke up. So i got angry and left her, now she is begging me to come back to her, she says she only sent those because she got upset when i said i didn’t love her anymore. So she called him that night and talked to him and sent him photos. She says after she sent those photos she felt guilty and blocked that guy.

When i patched up with her i really made her believe that i loved her. And i really do. But today i found out about the photos and stuff. She says she’s gonna change. She loves me, she wasn’t sure if i would come back or not so she sent hose photos.

I love her, i think she loves me too but not sure if she can really change or not. I am heartbroken right now. I don’t understand what i should do. She is 19 and i am 21

Sorry for bad English.

tl;dr : she sent her nudes to someone else the day we broke up, found that out after we patched up 4days later.