Other than your boyfriend...
Have you never had a past experience, maybe when younger, when someone tickled you and you either weren't expecting it, or weren't wanting it? It's possible that if you like being tickled, and the giddy sensation of someone you desire sliding their fingertips surreptitiously into your secret places, you won't experience the same ticklish sensation as you would if it was uninvited.
I remember as a child I was tickled here and there by family members and I despised it. Even though I can remember having a tickling fetish all the way back to pre-school, I hated being tickled by someone when I didn't want them too. I didn't realize it then, but it felt almost like being molested, it was unnerving and repulsive. On the other hand, whenever a girl I was sweet on tried to tickle me, it was an entirely different reaction. My underarms, for example, are ungodly sensitive to tickling, but I'll never forget when my first real girlfriend tried revenge-tickling me after I'd gotten her really good. She got her fingers in there and started tickling the hell out of me, and instead of laughing I became unbelievably aroused, and the tickling just sent wonderful shivers through my body.
Anyway, I just thought it could be the case that he doesn't illicit a ticklish response from you because you actually want him to touch you places you normally wouldn't let anyone else. Your ticklish zones can be incredibly erotic places in the right hands.
