My whole life just blew up

This is my first ever post on Reddit (wish it was for a better reason), but I'm lost, I don't have a support group to turn to right now. I don't know if I'm here for advice, support or what have you but I just need to tell someone.

Last week my wife (30F, married for 1.5 years together for 14 years) had me (29M) meet my two brothers for an emergency meeting. There she told us she had been having an affair with my older brother since before we were married. It had been going on for 3 years. I told my brothers to leave immediately, and after talking for a bit we went home. We booked a meeting with a couples counselor and she's been reading a book on understanding infedility every day (she did all that herself). She has been extremely apologetic and hates what she has done.

The first few days after almost felt hopeful, like this awful thing happened but we were talking, sorting this out. We could fix this. But as the days drag on, and we run out of things to talk about, the mood had become more pessimistic. She's been using more vague terms to describe our future. She's been talking more and more about my brother and how she misses him. I'm worried that by seperating them I'm pushing her right back into his arms.

I love this woman more than anything in the world and still do, but she says she still loves my brother as well. She says that while she sees a possible future with me, she's worried it's tainted and beyond repair. Every day she seems to miss my brother more and more. We're stuck stewing in our appartment growing more restless by the day, and I think absence is making the heart grow fonder. It's making her miss him more.

All this, and I can't feel mad at her. She's my best friend, we grew together, became adults together. She's my everything and always has been. I want to fix this, I want to keep her more than anything, but she isn't sure she wants the same.

I'm so lost, the only thing I know is no matter what direction we take nothing will be the same.