<human>: Can you give me the gist of the text in a nutshell?

First some background: Me and my brother still live at our parents house and my girlfriend of 3 years comes over often, sometimes sleeps over.  She is often at family get-togethers and what not. We are pretty serious and plan on moving into our own place together as soon as we can afford to. A little background on my brother, how can I say this, he is kind of a deadbeat. He doesnt have a steady job, doesnt go to school, mostly stays home and plays video games.  As far as im aware hes never had a girlfriend and is still a virgin.

Now on to the situation: the other night my girlfriend slept over and was off for the day so I told her she can sleep in and make herself at home and can leave whenever cause I was leaving early that morning for work. Both my parents had left too to run an errand, so just she and my brother were home.  She told me that my brother had knocked on the door to my room where she was and asked if he could talk to her.  She said that he told her he wanted to confess his feelings for her. That he had "strong feelings" for her for "a long time" and that he thinks he "loves her". She was shocked at this and told him that she doesnt see him in that way at all and is like a brother to her. At some point he then tried to kiss her on the lips but she told him to stop and that shes with me.  He stopped and kind of apologized but meant what he said.

He told her not to tell me about what happened, but she did and needless to say im not happy about it. What should I do? Confront my brother or just ignore it hoping that he'd get the message from my girlfriend and not make anymore moves?
<bot>: brother tried to kiss my girlfriend and told her that he loves her, should I confront him or let it go hoping he wont do anything more?