<human>: Condense the text into a few key points

Reddit, help me! Sorry, this will be kinda long.

I'm 28f, he's 22m. We've been living together for a year and a half and our relationship is pretty magnificent. He's seriously the best guy I've ever known, and so I just feel horrible when something he does annoys me (especially since I know that he would never purposely do something to annoy me, piss me off, etc.).

He has this humming habit. Now, if he were humming a song, that would be fine. But it's not a song. It's just this repetitive noise. A low hum that rattles his throat, then a higher pitched hum. Sometimes he'll just do it once, or twice, but sometimes he'll do it almost constantly.

I've tried to discern if he does it at certain times, like when he's thinking, or when he's stressed, or when he's happy, or whatever. But I can't find ANY pattern at all. And lately, it seems like he is doing it more often. He does it while he's eating. He does it while he's brushing his teeth. He does it while we're playing games together (which can be distracting if I am trying to think), he does it when he lies in bed to go to sleep (which can also be distracting because I'm a light sleeper, sigh!), he does it ALL THE TIME.

I have asked him why he does it all the time, and he says he's just clearing his throat. I asked if he needs to clear his throat while he's eating and brushing his teeth and he just kinda laughed and said yes.

Unfortunately, it just seems to be driving me further and further into insanity. I wish that I could just drown it out, but it's too random. I wish that I could just find it as some sort of comforting sound or something, but little noises like that just bother me to hell. 

What do I do? I don't want this to bother me, and I don't know how to get over it. And I'm afraid if I tell him that it bothers me so much, it will hurt his feelings. :(
<bot>: My bf makes a humming noise all the time that drives me crazy and I want to know how to get over it or confront him about it without hurting his feelings or making him mad.