The fact that you posted half of that speaks volumes about you as a person, but let's not go there.
If she can't get over the fact that you can't stand it and still wants to do it anyways, she'll eventually have to go - if she can't stop tickling you, who knows what else she won't be able to stop doing (eating, coke, sleeping with her co-workers, other things generally not healthy for relationships)?
That said... how bad can it really be? It's tickling dude... I generally just put up with it, because... well... it's a tickle. Tickle the shit out of her and turn it into sex - that way you'll only have to have to endure like half a tickle before you tun it on her and then you get sex out of it. Win-Win!