I agree with those who said that you should consider telling her....for *your* sake. And, that walking away is likely not going to work.....again for *you*.

So, do you think you could just email (or drop a note at her office) her your "confession"? That way you have some space / distance to deal with it yourself (and the effort of writing with the ultimate goal of letting her know might help clarify some stuff for you)? And, also you're not stuck with trying to deal with whatever stuff she comes up with in session?

And, after that, you could figure out what you'd like to do? If you want to go in and speak to her, tell her in the email (or however you make an appointment) that you'd like to do so. Or, if you want to just terminate and would like a last session, say that beforehand as well?