How to break up with someone that you fell in love with

So, I don’t want this post to be too long, I’ll make it short and sweet. I’ve been together with my boyfriend for about 4 months, I know, not that long, but anyways, at first we would see each other everyday (or at least everyday) and we were happy at the beginning, then all of sudden he changed, he started to hangout less and less, he started making remarks about my body (which btw I LOVE how I look), and how my attitude was changing. I love him oh so much, but I think it’s time to end things, but how do I go about doing that?

Any input would be helpful. Thank you!