If your primary concern is ensuring that you have 50/50 custody, then I think that you really need to listen to your attorney and hire a PI. Your W has already told you that she will fight against you having 50/50 custody.
Even though I know that you feel compelled to confront your W, don't do it until you have everything documented. I promise that confronting your W will get you no where at the moment. My H and I were together when I learned about his A. We were both looking at his phone at the moment the OW sent a text. My H lied through his teeth for 30 minutes about the text that we both clearly saw. I told him what it said word for word. It was horrible and made the situation even worse for me. I already knew about the A and now my H (the man I married and the father of my children) was standing in front of me lying to protect his A. Seven months later he still lies through his teeth to protect her. If you are concerned about the OM (and it appears that you have reason to be concerned), then I would follow the recommendations of your attorney.
I promise that whatever you are hoping to achieve from the confrontation will not occur. You may feel bad not saying anything and just letting it happen. But will you feel any better after you confront her and she continues with the A despite knowing that you know? Because she is going to continue the A until SHE decides that she is done not because you confront her about it. This is a marathon and there are no quick fixes to the pain that you are feeling. It svcks and I am so sorry that you are going through this.
Please don't let your emotions now jeopardize your future with your children.
