Hello DGB.
I'm going to make a few guesses, based on the assumption that you are close in age to your WW. She (and thus you) were mid-30's at Dday 5 years ago, meaning early 40's now. Your daughter was 7 then, meaning she's probably now on the threshold of high school.
I think you know from lurking here that your marriage is not in any version of actual Reconciliation as it is generally described here. There are so many things she hasn't done, or has omitted doing, or simply hasn't even contemplated. It seems clear that what is on offer from her is what you have. A lifetime of détente.
There is a phase of infidelity recovery often described as the "plane of lethal flatness". This phase arrives after the roller coaster of conflicting and wildly vacillating emotions after Dday, after the anger has ceased boiling and has reduced to a slow steam of resentment. Usually about 2 years out, plus or minus. It's that point where the BH lifts his head and looks down the road forward, and it occurs to him that, for the rest of his days, as far as he can see, the reality of his WW’s A will be a permanent Plus One in the marriage. It never goes away. Sort of a dull throbbing headache forever lurking just behind the eyes.
As an aside, this is one of the several reasons that the strong recommendation for R is complete, detailed disclosure by the WW, coupled with free and open discussion of it as often and as prolonged as the BH wishes. If you have to live with the Devil, it's best to get to know it intimately.
But I digress. It's clear that isn't going to happen in your marriage. Betrayeds tend to initiate D at various common nodes. Some betrayeds initiate D right away, as soon as the A is discovered. Some wait until the wild, passionate emotions subside and then, when they glimpse the POLF, they decide to D. However, many white knuckle it and soldier along. That’s you, out in the burning sun in the middle of the Mojave, staggering along, dogged determination or stubborn force of will or just habit, maybe a combination of all three. That's the 5-year mark.
Many remain married for life under these circumstances, even knowing they will never get the truth, never get 100% both feet all-in commitment to R from their WW. There are a lot of reasons. Sunk time. The kiddo. In your case, you describe points of light, small oases in the desert: some decent sex (though is Sir Topham Hat enjoying frequent trips to Tonsil Town?), some laughs, steady housekeeping. To me it sounds like a species of Stockholm Syndrome – often, for a BS, the years of marriage following Dday are a species of that – though maybe it’s enough for you.
There is a thing I call that "ephemeral matter of the heart". Over and over we see betrayed spouses bemoaning the reality (or the perception) that they aren’t getting what the AP got in terms of passion, attention, generosity, sexual brio. There is a logical explanation for this, which is proffered by a poster above, but logic does not necessarily dictate the heart’s desires. As a steady good provider and generous companion, you absolutely deserve what the AP got, in the sense of "deserve" as a function of cosmic debit/credit.
As you know, there are plenty of posters who decided to D around the 5-year milestone. It’s another common node, for precisely the reasons discussed in this thread. It’s why I think you found yourself surfing the internet about affair recovery, finding this place, creating an account, and posting your cri du coeur.
Here’s my 2 cents. You’re at the place where the adage about "keep doing what you’re doing/keep getting what you’re getting" clearly applies. What you’ve got is what you’re gonna get. Is that enough? Early 40’s is plenty of time to start over. If you’re gonna split the household and become a co-parent to your daughter, pre-high school is a better time to do that than either mid-high school or, worst, ages 18-22. If you split now, you could even strategically plan the household location to get her into the high school of choice (if you reside in a metro with multiple school districts).
With that in mind, I’d like you to look in the mirror and have a conversation with DGB at age 45. Age 50. Age 55. Will that DGB thank the present-day DGB for choosing, yet another day, to not take steps to end the marriage? Will the future DGB look back over the past 5 or 10 years and thank the present DGB for his decisive action? Every day you make a choice, my friend. At the end of that day, the choice for the day is irrevocable and irrecoverable. Will future you be happy that present you has chosen to give those days to this level of married life?
[This message edited by Butforthegrace at 7:12 PM, Thursday, January 20th]