That must be hard. I'd like to share my hugs as well.
Since you ask for advice... I don't have much experience, but I have a friend whose parents "broke up" when she was a little kid. However they stayed together, lived together, raised the kids together. At that point they were friends, roommates and parents, but not partners.
They stayed married as well, and only divorced after all of their kids had left the nest.
What was hard for my friend was that she only learned about it when they got a divorce. They basically told her "we haven't loved each other for 18 years but stayed together for you guys". That made her feel guilty and was painful. So I guess my advice would be, if you do a similar thing, to be honest. I think kids can get used to what they are raised in, and a lot of kids have parents who aren't together. Here, they'd just have the advantage of still living with both, which would probably be much more stable for them.
What I don't know is how that would work for you. You obvioulsy not only still love her, but desire her as well, and it could be hard for you to keep living with someone and be constantly reminded that she is not attracted to you or any men. It would be a very difficult transition, but I think it might be possible if you both try hard to make it work.
You might need time off from dating for a bit to get over it, you say you were fine with poly when you thought she liked you, but not now that you know she isn't attracted to you. Maybe a break is what you need. Afterwards, though, I think if you date you should make the circumstances clear to any girlfriend you have: "my wife is a lesbian. We are staying together to raise the kids and as friends, and I love her and care about her." It's important that they don't think you're staying together as a facade, when you actually do love each other.
Your relationship can be of friends, or non-sexual partners. You just need to be clear about that. It wouldn't be fair to a girlfriend of yours if she thinks you're together for now, but will leave your wife once the kids are grown, if that's actually not your intent at all (for instance).
I think you will need to work out some issues with your wife, namely her jealousy. I think it could be due to her insecurities as she knows she can't satisfy you sexually, and therefore might think other women are a threat to your relationship. Either way, it's important to sort that out so you can have a sex life / love life outside of her. I think that will be an important part of the success of this relationship with her, if you do stay together, that you have an outlet to make up for what she can't give you. If she tries to prevent it, it could make both of you unhappy and ultimately destroy the relationship.
So there, that's all the advice I could think of, I hope I helped somehow... if I made wrong assumptions about your situation, feel free to correct them. And good luck with everything!