This is the truth. ^Friend, you love who she was, she’s not there anymore, it’s a shell and some narcissistic POS has taken over.
Even if she did come back she'll never be the wife you thought you had. The succubus she is now killed who you thought your wife was when she slept with the gym rat. You can bet on the fact that everything she has told you has been minimized and all the blame shifting is 100% tripe. She owns the cheating, all of it. You were in the same marriage and you didn't cheat.
Charge ahead with seeing a lawyer, filing, and splitting finances, who gives a rip what she thinks about it. She didn't ask you before she opened up your marriage. Take a firm, decisive stance now and you will gain back the 2 months worth of ground she made before you found out. She is no longer family, she's your nemesis. You need to recognize this or she will drag you through hell and take you to the cleaners. Get strong and stay strong.