Don't be rude. There's a word that is used for how you should be. "Meh". Some use "as if". It means you're not hanging on their every word nor care what they have going on. You're not angry, you're not rude, you're just meh. If you've been a safety net or a shoulder to cry on you have to stop that. They want out so they can feel what that might feel like. Sometimes a WAS/WS will convince themselves in their fantasy that you were never supportive of them. When you show them what that really looks like to not be supportive of them it can help them see how wrong they were.
There is no magic cure for this nor is this a guarantee. What doing the 180 will do is give you your best chance at saving the marriage. Some do it and it fails (even though admittedly a lot of them don't follow it strictly). Some do it and it succeeds. It worked for me. My own WW played me and strung me along for two years. Back and forth. Finally it was ME that said I've had enough of this. I filed for D and I was ready to move on. I was the king of meh. She lost her job because of her A. Oh really? I said. Huh. That was it. Meh.
It flipped the script. She realized fantasy land wasn't real and she had some hard times ahead of her. I went from pursuer to pursued. The 180 and my "meh" attitude gave me strength. She couldn't get anymore emotional rises out of me because I was like Rhett Butler: "frankly my dear, I don't give a damn."
When you think about that movie, it worked for Rhett too. Scarlett treated him like crap until the day he walked out. Then she was begging him to stay but he had already 180'd her and moved on.
Life is too short to be someone else's doormat. Everyone who posts here are good people. They don't have to hang around and be emotionally abused by a fence-sitting WAS/WS.