Breaking up

I've been with my boyfriend for about 5 months, we've had a great relationship and he's become one of my best friends. However I'm not really sure I want to continue this relationship anymore bc I just don't feel in love with him anymore. I feel like he forgets about me often and doesn't always try to make time for me when I go out of my way to make time for him. 
I recently met this guy at work who makes me feel that spark of excitement when we hang out and it just reminds me how I don't feel that with my boyfriend. I still want us to friends but I just don't know how to go about the breakup speech