(34M/33F) Time to call it in a 12-year-relationship?

Me (34M) and my wife (33F) have been together for almost 12 years. We’ve had our ups and downs like every other couple.
Around 4-5 years ago, we more clearly started lacking physical intimacy. My wife told me that she was super exhausted from work plus doing her phD at the same time. I understood but asked that she speak with her supervisor (or w/e it is you call someone to whom you are doing the PhD) as it was affecting her and our relationship. She would not.

Fast forward 2 years, nothing has changed. She does not want, and i do not want to try cause getting shut down every time really eats you inside. Even more casual closeness like snuggling before sleep could make her say that she doesnt want sex right now.

Later on she told me that its ok if i go out and sleep with someone, since out sexual drives did not match. I declined this and told her that thats hardly any. She still insisted that she is just exhausted from the PhD and hinted that when it was done, things would change. (Spoiler, they did not).

This topic repeated itself throughout the year, until i accepted it and had my fling(lets call her Ana). My wife seemed to be fine with it. We met a couple of times, and on the 3rd my wife joined us. We didnt meet with Ana anymore after that, as she settled down with someone else.

Fast track 6 months. My wife dropped the bomb that she was not sexually attracted to me anymore. And that she has had this dark empty feeling for a long time that if she does not date (or “try”) women, she would regret it but at the same time she was terrified that she would lose me in the process.

After i somewhat processed the shock, i told her to do that if that is what she wants. I didn’t and don’t want ti be somethings she just settles for, cause she fears change.
This was last autumn.

Now we arrive to present date. My wife has been seeing this woman (“Dana”) for the course of this summer. They have only met a handful of times. But texted A TON. Like real late in to the night which was really noticable as she used to always go to sleep before me. And as for me, I am also now seeing someone outside of my marriage.

She claims her feelings for me have only increased after this arrangement now that she has this “outlet for her lesbian energy”, as she put it.

However i do feel the quite opposite of what she is saying. We’ve had sex once during this setup. But also.. I dont want to have sex with her? Now neither of us are initiating sex.

I do admit i am somewhat jealous when she comes home from a date with her, seeming so happy and full of life.
And I just watch and think how I do not make her feel that way. Ie. on her last birthday i took her to this carneval themed park. But she wanted to leave early, not go to a restaurant but rather order something to home and watch a movie. She ended up doing her crafts at home.

I think that she deserves to be someone with she can be her 100% self.
Moreover, I think i deserve to be with someone who wants ME, and not the things i can provide (a home, safety, companionship, etc..) She says she loves me now more than in a long time. But. What i feel between us is more of a sisterly love. We live together. We are roommates who share a bed. And looking back the slow transition during the last 4-5 years? I was blind.

I guess this was more of a vent to figure out my thoughts. To accept things as is (living together but dating other people) or to call it quits and start this dating shit all over again.

TLDR:
My partner of 12 years turned out to be a lesbian.