<human>: Me and my girlfriend have been dating for 18 months. The first few months were great, there were no problems at all. We were very happy together. But recently, it has been different. Three months ago, she lied about talking to her boyfriend. If they were talking, it would not have been the end of the world, but she lied to my face, and that's the problem. This happened one other time. 

I still don't trust her after 3 months. I told her last week I am no longer happy with her but have yet to break up with her. I feel like I owe her something and this is the least I can do. The reason I feel this way is because I have depression and she goes through a lot emotionally for me. I don't know what to do.

Thanks.

Summarize the given text in a few sentences.
<bot>: I told my girlfriend of 18 months I wasn't happy with her anymore but I can't bring myself to breakup with her because I feel like its the least I can do. What do I do?