I love her so much, and I know there was no intention behind it, but can you love someone, and do this? I’m just wondering how can I build that trust up again.

It was some app on Facebook about who your valentines should be and it was some lad she use to live with whilst at university with other friends also, and no there was no mention of me, and regarding the explicit conversation she did state she had a partner, but still continued the conversation Aswell as thanking him for saying she had nice lips that would be good for you know what and she just laughed it off and thanked him Aswell as continuing the conversation. We are great when we are together, now I don’t know if that’s because I know she is with me or what I don’t know, and her girlfriends in my eyes are of the naughty side shall we say so I know what they would do on a night out, and I feel she would follow, but apart from all that lol I honestly do love her and would do absolutely anything for her,but I suppose the question is can I stay with someone after feeling like this.