You have to take back your respect here. If you aren't okay sharing your W with OM than you need to draw a boundary with actual consequences. She is cake-eating right now. Why would you wait? She is lying and cheating and disrespecting you. Do you want to share a bed or house with a person like that?
If you let her, she's just going to keep doing this. Remember, you can't nice her back.
W 34 Me 42 Married 7 years together 8 0 kids 1 beloved dog BD 4/6/2018 I moved out 4/7/2018 I moved back in alone 8/05/2018 I file 3/06/2019 D official 5/7/2019