Well sometimes things happen that point out to us just how screwed up things have gotten.

Do I think you should go all confessional? No.
I think you have realised something has to give, now you just need to figure out what that is.

You and your partner need to have a long talk, maybe mediation, or couple counselling.
If your partner isn't up for changing how things are you have a tough call to make, since I assume you don't feel you can continue as things are indefinitely.
And this isn't just about you your girlfriend is obviously not getting the most out things.

Here's wishing you all the best.