Knowing that it makes him uncomfortable is what I would focus on, if I needed to hold back.
I'm with LR, to me love is a verb, it's something I consciously choose to do. Feelings are gravy (extra). So, a very loving thing to do is to make a partner feel comfortable and loved, whatever that means to them.
My dad once gave me a lovely lecture about love, and how he had learned to make a cup of tea exactly the way my step-mom liked it. Not the way he had learned to make tea, but the way she liked.
That's never been so obvious to me as now that I have two boyfriends. They each like to be loved in fairly different ways.
Talk to all your friends who will listen about your crush and use your l-word with them. Pound it out on your keyboard. And then find other ways to express to him. One of mine hasn't said it, but I recognize that he's uncomfortable with me saying it. I say things like 'I love the way you do _____' (whatever). Or 'I love it when you __________' (do nice things for me)(whatever).
Love is that condition in which the happiness of another person is essential to your own...
Robert A. Heinlein
Me: female, bi, (formerly hinge of a vee)
with FirstBoyFriend (FBF)(moderately long-distance)
and no longer with CurrentBoyFriend (CBF)(who lives in the apartment building next door)