open marriage

He said a married woman will have little trouble finding men to date her, but a married man will have a very difficult time in the dating world.
This part is so true.

My thought is do what is best for you regardless what your W is doing or plans to do. Legal advice is the first thing you need to sort out. Do not depend on what you hear will happen or what someone else did. Legal actions depend on locations and the different divorce rules in place in your legal area and the lawyers involved.

Welcome back to the club you rather not belong to.

Just asking here, but how do you know that she is having an exciting sex life? I wonder whether you have assumed this or do you have independent evidence? If you have evidence you have my sympathy. Wow that would have pushed me throughly over the edge. 

Apocrypha has a very similar story of a W who declined intimacy with him, but clearly had a desire for it elsewhere. 

Also, M women can get sex anywhere? I’m not divorced yet, that is news to me. 😊

Sufferinhubby it still might be to your advantage to consult with a lawyer even if you don't want to divorce right now to protect yourself from unknown consequences.

You spend time with her and you aren’t getting any! 

You may well be right, but appearances can be deceptive and assumption is usually worth avoiding where you can. Anyway, your focus should be on you and your journey forward. Is it covid restrictions or the fact that you are currently married which is your difficulty? You can’t do much about the covid restrictions, but if it’s your marital status is it disrupting the home for your children which makes divorcing problematic? It is very difficult to weigh up the risks and benefits. 

Perhaps you haven't been paying attention. It's a very general statement that may need a couple caveats, like height/weight proportional, a decent personality, a sense of humor and the ability to engage in interesting conversation. And foremost is the willingness to go outside the marriage. And remember we are talking about sex, not the early rounds of working out a marriage agreement. 

You're married to a happy woman?
I call that a win.

I'd been suggesting picnics, two blankets, 6 feet away, for the would-be outsourcers. When it gets warmer, that may be worthwhile if vaccines aren't out soon enough.

Where's your profile posted? I found good luck at OKcupid. Nothing at Tinder, Bumble, or Coffee Meets Bagel. The latter three may be full of women repelled by a married man actually admitting it.

OKcupid let me choose exclusively married women. I didn't want someone planning to "steal me away". I wanted that extra roadblock. 
Feel bad that I only got to date Kathy the one time. (My wife's reset made dating no longer so urgent and an unnecessary cruelty) Kathy had been having terrible luck finding a FWB.  Lots of flakes, no shows, liars, jealous monogamous girlfriends... Someone's out there, friend.

Want to run your profile past us? Maybe we can think of ways to tweak it some.

I've been down this road in the latter years of my marriage as well. We ran that program in various iterations across 3 or 4 years.
Within that timespan, I found, as your friend advised - non-monogamy and low-investment/commitment sex is something highly sought after by men, and less so by women. I'm not unattractive by superficial standards and am often considered "husband material" (which can be a detriment in the non-monogamous sex world sometimes). It was about a full year after Mrs Apocrypha relatively easily found a partner that I found one suitable and sustainable. And I live in a metropolitan city. I can't imagine what it must be like in a pandemic.

I also found that the "I am too old for sex" Mrs Apocrypha (then late 40's) VERY quickly flexed a robust and experimental sexual appetite with her new partner, doing things and talking about them that would likely be quite shocking to casual porn viewers.

My criteria for agreeing to this little experiment was that we both are in on it - both sides. And, that I carry on with it only as long as my own sexual involvement with her improves to the extent that it ceases to be a crisis. Otherwise, why do this instead of putting our energy into being better ex-spouses and co-parents - since the problem OBVIOUSLY was not general sexual aversion on her part, as she insisted.

As baza mentioned above and as I always council people who try this out - yes, you might get some sex in your life here and there, under specific conditions and as events, but this isn't remotely sex in the context of an invested relationship that has no baked-in limits on it. In other words, you are still in a sexless marriage - which is about more than simply the absence of sex. It's about the person you live with and love - demonstrating day in and day out - that they do not see you as a viable sexual partner. That's an incredibly toxic situation to live in. An open marriage, an affair, or a separation - gives you more empirical data to demonstrate that the problem isn't her sexual aversion in general; it's an aversion to you or the marriage to you. Every day.

Open marriage together with a partner or one-sided without one, or a closed celibate marriage - it doesn't matter. You still are faced with a dysfunctional relationship in your home, in which your partner is so averse to you, she'd rather risk the marriage and everything associated with it than sleep with you.