Pac you have to build a life for yourself that anyone would want to be a part of, full of fun activities, outside interests, and engaging friends. If you can do both of those things -- completely emotionally uncouple from her (fake it until you make it) and build an amazing life for yourself, she'll clamor to come back and if she doesn't you won't care. That's your only winning path out of where you are, but getting there is going to be uncomfortable, and more painful than you feel today, because it will go against your white knight nature.
You've been trying to "nice your way back" for the last 12 months.
It's not working, it will never work.
You cannot placate her, you cannot "prove your love" through acts of giving and support.
You also cannot push her away by withdrawing support.
She has chosen her course of action, and as of right now, nothing you do will impact it.
Your shortest path back together is to go the opposite direction.
You need to make things worse before they can get better.
Are you willing to do that?
If not, you can expect many more years of the same thing you have now.
