<human>: Can you succinctly summarize the text in 1-3 sentences?

I have been with my current girlfriend for 3 years. We started dating in high school and continued into college (we go to the same college). Our relationship is okay, but my feelings for her have never been as strong for her as hers are for me. 

From the beginning of our relationship, she had said me watching porn was a deal breaker. About a year ago, she found out I had been watching porn regularly. I had lied to her many times before this and told her I had not been watching it. We had a huge fight and almost broke up, but didn't. I went to a counselor for several months and stopped watching it for a while. But, I am now watching porn again and feel terrible about it. I have already broken her trust once and now am doing it again. I feel unworthy to be in a relationship with her because she is beautiful, kind, and caring. 

Besides the porn issue, I feel strong attraction to other women on campus. I have never been with anyone but her sexually and feel like I am missing out on other experiences. When she asks if I look at other women I always say no, even though I do. I know the grass is always greener, but it's hard to be sure when I've only been with one person. 

I know I am a terrible person. But how do I handle this? If I broke up with her she would be totally blindsided and absolutely crushed. Do I break up with her now? We just started a 3 week long break, and that feels like a recipe for depression for the both of us. Please help me. If you would like more detail about our relationship please ask, I am writing this hurriedly.
<bot>: I have been with my girlfriend for three years. Lied to her for several. Lust for other women. Need advice on what to do or how to break up.