So me and this guy stared going out maybe a few weeks ago and one of my friend has a crush on me and I don’t know how to let him down easy because I don’t want to ruin our friendship I can’t think of any good nice way to let him down and it’s stressing me out because he is a good person and deserves someone good for him that can return those feelings I did once but then well I met my boyfriend and we just feel together like a puzzle piece

Any ideas how to let him down easy??