How long did you like him before you told each other you liked each other? Honestly, as harsh as it is, if you don't like him you need to end things ASAP. The longer it goes on, the more it'll hurt. If you do like if you, but you're just getting stressed by him being pretty full-on, maybe just have a conversation with him about it? Just explain that you really like him, but you have other things in your life which require your time and attention. Maybe organise times that you'll keep open for each other, and times where you need to have alone time to focus on work. Just explain that it isn't because you don't like spending time with him, but that you need to focus on your work and it's feeling a bit intense.