Dad1st,
Sorry you need to be here. Sorry you're going through the wringer, on the roller coaster, feeling bipolar--all of which explain what this kind of revelation/discovery makes us feel.
Your wife is in a similar stage of her own, one in which she yearns for the new self/life she wants to embrace, and one in which she fears to leave the old one, which is the one she built with you (and your children). I once told my now-ex that this was like him being a dog who is staked out on a clothesline, with the lead to the collar attached to a clothesline, and the dog is running the length of it back and forth. Look over here! A squirrel! Look back there! My food dish. I want the excitement of that squirrel, but I need the security of the food dish.
You, on the other hand, have only fear and a transformed life, with neither "squirrel" (pursuit and fulfillment) or "food dish" (security).
You are torn because it's very difficult to stop being a loving spouse. Unfortunately, that is exactly what you must do, because your wife has already made it clear that she no longer is acting under that same understanding. Indeed, she wants you to remain "supportive" and to accommodate her (with the request to "live like roommates"), without reciprocating that support. It's entirely wrong for her to say the hurtful things she is to you (such as about life making sense), as if you won't be hurt by them, and as if she is entitled to say them to you. She is not able to empathize with your situation, but expects you to empathize and accommodate her own.
It seems as if you have already asked yourself whether the situation you have now, and the one she says would suit her, are not acceptable to you. The logical next step, then, is to explore your options for divorce/separation, and for custody/child support, with a lawyer. Go by yourself, and don't tell her. If that seems like a betrayal or too cold hearted, tell yourself you are seeking information only. Also remember that a so-called intact marriage with Mom stepping out with other women while long-suffering Dad keeps the household running is not a healthy situation for children, and models dysfunction. I once heard it said, "You don't stay for the children, you leave for the children," and that made a lot of sense to me. Just as you don't stay "for the marriage," which is no more than the two people in it and their commitment to each other, you don't "stay for the children," when the resultant family life does no one any good.