I nrever went through a situation like this, but maybe I have some insight.

Though you find him lovable, this is not a nice guy. He knew you were attracted to and cared for him before you told him. You don't strike me as someone who's hard to read. This guy led you on. He's into head games. Has he always been single? Of course, he's had relationships. But a 40 year old guy who's never fully committed is into himself. Or he's into his mother. Or he's cheap as heck. Or he's a skirt hound. Or he's just a weirdo.

Stay civil, but drop all pretenses that you two are buddies. You are lonely. He saw that and exploited it to kill some time.

You don't conform to his image of you that he had. What a snot. Who says stuff like that? Nobody decent. Nevermind "close friendships" with single guys your age. A guy either wants to date you, or he doesn't. This guy has played you.

He cared for you "as a person." He wasted your time is what he did. Cultivate female buddies. Straight single guys your age are not candidates for deep talking-half-the-night platonic friendships.

He got bored with you, and that's lucky for you. Don't tell him anything else personal about yourself. He's a bit of a voyeur. He got you to, psychologically, take your clothes off, so he could scan you. The guy's a creep. No wonder he's 40ish and single.

You are lonely and ready to accept a quick fix for that. Slow down. You have not learned to keep appropriate personal boundaries. Not your fault, just a blind spot you have.

40 is still young. Work isn't the best place to seek out intimate relations. Find other venues. You'll miss him and feel hurt for awhile. In time, that will abate. He's bad for you. Keep a distance away from him.