It's not the worst thing, so don't feel too bad. ^_^ At least you're intentions are harmless. If it's causing you stress and you don't like it, go to talk to someone. Is there anyway you can gradually cut down the amount of times you touch someone's neck and find a distraction to take the place or something? If it bothers you, do get help.

I think it sounds kinda cute and quirky to be affectionate like that to your boy friend. ^_^ (Don't call yourself weird)