<human>: A little backstory; he and I have been together for a year and 3 months. Back in February I took him to see one of our favorite bands. We had only been together for 6 months back then and this was one of our bigger dates (we usually just hang at my place. Slight LDR) he told me that a friend would be there and he wanted to hang with her a bit (they met online like us). He told me she had a huge crush on him and told me not to be mean because I have jealously issues. The entire night (just to show he was mine and she better keep her distance) I was all over him. Kissing him, leaning against him, and even had her take photos of us making out. But there was something I didn't see. When he said goodbye to her, he went to kiss her on the cheek and she "misunderstood" and kissed him on the mouth. He kissed her back (in his words it "lasted longer than it should've") and never told me until I went snooping on his fb (another girl was harassing me and basically Internet stalking him and I was checking to make sure she was gone.) and saw messages about it from her. I feel so hurt and betrayed that he never just told me about it. We plan to get married in a few years. I love him so much and could never leave him but I'm so upset. I told him to block her on everything he used to communicate with her, fb, Skype ect.
Was I too quick to forgive? How can I ever fully trust him again? I have jealousy issues from past relationships and severely hurt.

Can you condense the text into three sentences or less?
<bot>: My boyfriend kissed another girl months ago and didn't tell me till recently. Was I too quick to forgive? And how can I ever trust him again?