VC12, if you are sure that you want to divorce, you don't need proof, just begin. I was sure I couldn't live with the continued lies and wondering what he was up to. I found pretty good proof, although he still denied being gay. My gut knew.
He didn't want to divorce at first, but I did. I got it started and in the end he agreed to what I said. (I had the money info too.) In your case, with kids, it will be different. I guess I'm saying you get to choose even if he doesn't want divorce. Move fast before he gets nasty. Talk to an attorney, usually free initial meeting. Go online to find county and state info. Make copies of all documents, keep in a safe place just in case.
You can do this.