Toasted so sorry you are here, I truly mean that. My WW is also involved in an affair. It is going to be the worst rollercoaster ride you have ever been on. I hate to be the one who tells you that.
Start the readings suggest above with Sandi's rules and Sandi's reflections. You will get a great deal of insight from that. BUT, make sure to read them all.
Your question about being a Christian by doing 180's. I would tell you this way, by following the advice, even the tough love stuff is how you are standing up for your marriage. By making it through this and doing everything you can within the process you are fighting for your marriage even if its tough love or being silent.
Me 41 W 33 M 2013 Suspect A 11/15 Confirm A 1/16 She moved out 2/14/16 Stepson 13 Stepson 16