OK ... from what you've written, I think you've been handling yourself pretty well.
I think your W may be telling the truth, if she never met ow. It's hard to touch someone when you're not in that someone's presence. In any case, this response assumes she has given you an accurate outline of her A. Some WSes do, in fact, turn pretty much on a dime.
Phone sex with someone other than one's partner is betrayal. Video sex with someone other than one's partner is betrayal. Now that I think about it, what you describe is, in fact, not the same as what we usually mean by 'P(hysical) A(ffair),' even though physical pleasure was part of it, but whether we call it an EA, a PA, or 'TA' (Technology Affair?), or something else, it's still infidelity.
I think it's great that you know you want to keep your M together, but ... my reco is to separate what you want from what you do. You can want to stay together for healthy or unhealthy reasons. Before you commit tor R, make sure the preponderance of your motivation is healthy. You can lead a good life after D, too, even with young kids. Talking with a good lawyer about rights and duties is a good step.
My reco is to keep asking questions. Every answer that's consistent with previous answers builds trust. Every question is an opportunity to to lie. If you change your questions around - I asked the same question at different times and the same question in different ways - and if you keep the questions open-ended, you're likely to get a sense of truth/falsehood that's much better than a poly can give you.
A poly is useful, IMO, if you come across an issue that can be resolved one way or another with a yes/no answer.
*****
IMO, in R
BS heals BS;
WS heals WS;
together BS & WS heal/build/rebuild the M.
You can provide emotional support to each other, but you have to heal yourselves. The grief, anger, fear, and shame you feel are in you. You're the only one who can resolve those feelings.
The fear, shame, grief, and anger your W feels are in her. She's the only one who can resolve those feelings. To R, she has to change from betrayer to good partner; she's the only one who can do that work. To heal herself, she is the only one who can build up boundaries against letting another person take over her will.
I think a good therapist/IC is essential for your W. A good therapist/IC can help you process your feelings and evaluate what's going on in your life and M.
Do not commit to R unless your W is willing to do the very hard work she needs to do. R is eminently doable for any partnership that does the work. It is impossible unless all partners do the work. And even though it's doable, that doesn't mean you have to do it. If you don't see yourself happily growing old together, maybe now is a good time to split.
*****
Obviously, I don't see the gender of the ap as a necessary part of R. That is, if your W decides she's gay, she is not a good bet for the long term. If she enjoys sex with you, though, she's somewhere in the bi part of the continuum. A bi person can choose to be monogamous.
*****
Being betrayed is the worst experience of my life, and I'm not alone.
If you feel awful and find yourself feeling worse and worse, that's par for the course. If you feel like you're in shock, that's par for the course. I think I was in shock for 3+ months, and I didn't recognize shock for 4-6 weeks. I was on a roller coaster down for 3-6 months.
But feelings are like waves - you can't stop them, but you can ride them.
*****
Some recommended reads:
http://www.survivinginfidelity.com/healing_library/reconciliation/what-every-wayward-spouse-needs-to-know.asp - if this resonates with you, I suggest printing it off and giving the printout to your H as 'something you found on the web.' My reco: DO NOT tell your H about SI until you're sure he's on board for R.
http://www.survivinginfidelity.com/forums.asp?tid=361740&HL=14993 - serjr threads for newbies
Tactical Primer:
http://www.survivinginfidelity.com/forums.asp?tid=235051
Boundaries and Consequences 101:
http://www.survivinginfidelity.com/forums.asp?tid=385631
Setting Healthy Boundaries:
http://www.survivinginfidelity.com/forums.asp?tid=231851
Before You Say Reconcile:
http://www.survivinginfidelity.com/forums.asp?tid=406548
The Simplified 180:
https://www.survivinginfidelity.com/forums.asp?tid=598080
20/20 Hindsight: What I Wish I'd Done:
http://www.survivinginfidelity.com/forums.asp?tid=161389