Well I'm only a little over a year out with recon and piecing so I, probably a little too often, think about calling it quits.
In the beginning a minor inconvenience would put me in the state of mind to question what I was even doing. Now it's mostly when we just have spats that are more than just annoyances and when I have days where I think "god I miss the way he was in the middle of the A." Not because I enjoy being treated like crap but because he wanted to spend time with OW and because of his guilt he felt compelled to do twice as much around the house. He wasn't working like 60-70 hours a week. He was working like 50 max and would make dinner at least 2 times a week but usually it was more. Lifting a lot of mental load off of me so I could have me time. Now he's comfortable working like a crazy person because he knows I'll pick up the slack. And if I so much as breathe that it's a lot and I'm trying not to be resentful or unappreciative he then becomes a puppy and lavishes me with affection, attention, and things. So then I feel guilty. And I feel like maybe ending it would've been easier than this shame spiral I now have to deal with. Sometimes it's a Tuesday night I just wish I had space and I wish I would've ended it.
In any case it's fleeting. I love him. And he'd crawl across gravel if I asked him to. So I can't say he doesn't love me. And because we always have our friendship and that love to fall back on I don't really stay questioning it for too long. Love comes in waves. It ebbs and flows. It transitions. There's passion and there's companionship. And sometimes it's just being alone together. I have days where if he says one more word I want to smoosh his face. And days where I want to jump into his arms the second I see him. And days where I really just want to be alone like completely alone. But as far as I can tell all of that is all very normal.
In your situation though. You guys just went through a really big transition. Your daughter left the house. That does things to people. Marriages fall apart. People fall apart. It's a huge life change the kind that makes people reassess and question things. It's also the kind of change that if you didn't plan appropriately for it, it can leave you feeling empty. Empty nesters can mean a lot of things. Almost 20 years of your life was dedicated to full time parenting. And now it's simply not.
Even if none of that's the case, why is it that you think your marriage is what should make you feel fulfilled? It's not your wife's job to make you feel that way. It's not your marriage's job either. Your wife is your wife because you love her and want to spend the rest of your life with her. Your marriage is a marriage because that bond and commitment was/is important to you to show the world you love and cherish your wife, and your family. Neither of those things exist for your fulfillment. Love isn't' about you. Neither is commitment.
I'm doubling down on LH's question of why do you think ending the marriage will make you feel fulfilled in the future? And I'm adding have you discussed this feeling of being unfulfilled and all the little satellite feelings that go along with it with an IC? Also have you really sat in why you think a drastic change (just in general, not necessarily in direct relation to your marriage) would made you feel fulfilled again?