"I'm not a good friend right now. I'm not a good boyfriend," the Glee star tells Details in its December/January issue.
But it's not personal.
"It's not that I'm selfish," he says. "I'm just focused."
Working 15 hours a day leaves the actor little time for romance. "It's been a while," he says. "Meeting people, you wonder, 'What does this person see in me?' "
It wasn't always so. Morrison, 32, fondly recalls being smitten with the opposite sex as a young actor performing in musicals in New York. "I definitely hooked up with a lot of girls when I was a young guy on Broadway," he says. "It was exciting. Very joyous and free."
Still, he remains a bit conflicted about his attractiveness to women. "I'm not comfortable with the idea of my sex appeal, but I know in my job I have to use it," he says. "I wish I could say I got to this point in my career based on my talent, but I don't think that's true."
The maturity Morrison found on the other side of 30 allows him to be a teacher not just in the Fox show but also on set.
"I am a teacher to them," he says of his younger castmates, whom he refers to as "the kids." "I've taken a few under my wing."
And he wishes some of them could be less publicity driven. "I find myself learning a lot from the set," he says. "I do look at stuff people on the show are doing, and I don't judge them, but I question it. I say to myself, 'Keep quiet.' Fame. It's like a handgun – in the wrong hands, it's dangerous."