<human>: My boyfriend and I have been dating almost 2 years (both 21). He is very nice and treats me really well, and I've seen his life change drastically for the better since we started dating. Over the past few months I feel like I don't have that same love for him anymore, like I feel like we are really good friends, I trust him and care about him. But I'm not physically attracted to him as much anymore, and I find myself thinking about other guys in my past.. Also we've talked about marraige and a future together. Some days it sounds great, other days not.
It would be heart breaking to break up with him, but what if there's someone else out there who I would be happier with? Really just don't know what to do here..

Condense the text into a few key points
<bot>: Having mixed feelings about my bf after almost 2 years of dating. Don't know whether to break it off or stay together.