Me (27M) found out my girlfriend (23f) was talking to a guy behind my back, what's next?

So basically I have been dating this woman seriously for the past few months, we both come from conservative backgrounds and expect to get married eventually. We set boundaries early on in the relationship she wanted to before and I agreed, then later I found out she was talking to another man who had made his intentions clear early on and I confronted her about it , she removed him but kept talking to him behind my back because she "felt bad" then she told me about it and blocked him. now she told me she spoke to him again for a couple of days because he kept on spamming her, she told me that she never said anything that would damage our relationship and that she felt bad and did not want to hide things from me and has sent me a long paragraph asking for forgiveness and saying she will never do it again. I haven't responded yet.

I understand that she recognizes her mistakes and wants to make things right but at the same time I feel hurt and disrespected, I never crossed any of her boundaries and did my best to be a good boyfriend to her.

TLDR: My girlfriend spoke to a guy who had feelings for her twice after I told her not to and I don't know whether to forgive her or end the relationship.