This is a tough situation, if you're wishing that she would break up with you, definitely don't get married yet bro. I've met a few girls that didn't like tickling all to well(so they said) but as long as I did it lightly and adjoined with different things they didn't mind. I've only met one...
From personal experience,
I had a gf for about 6 months, one day we were at her house and I kind of joked about the idea of bondage in a way. Well I was tickling her then she got mad(kind of a play mad though) and i asked what was wrong? and she was mad because she couldn't tickle me back...