Hide a voice activated digital voice recorder using velcro and stick it under the front seat of his car.
Pay cash for the device so no one can ever prove you bought it thus enable to deny you did it if it's found.
Practice with the device so you are adapt at using it and placing it but don't leave your own voice of the device in case it's ever found. No proof it was ever in your possession.
You can buy it, get a cash receipt and then, as long as it's not found by someone else, return it in 30 or 60 days whatever the return policy is.
Most people feel very secure discussing their affair and/or marital/divorce strategies in their car. It's the best place to snoop and the most predictive information and if you do it once for a couple days it's not an obsessive compulsion....unlike spying on something like a cell phone bill usage report where you sit there hitting refresh every 20 seconds for 9 hours straight.
Most likely your husband wants to cake eat and keep cake eating so I'd anticipate he is still in a relationship with OW to some extent. Maybe not...but, you need to KNOW the truth about your life...not just guess or hope. Marriage recovery is NOT rebuilt upon trust - it is rebuilt upon TRUTH (and if you don't know the truth, you get it yourself).
As far as his parents....read some Cloud and Townsend about Boundaries. It sounds like you don't have too much of an issue turning the other cheek so you can handle them is small doses but I don't think you should ever be with them alone (without your husband) and certainly shouldn't spend the night there. A man should leave his parents and cleave to his wife. So you don't HAVE TO be in any relationship with them whatsoever. They are not friends and supporters of your marriage and they are enablers of their son's behavior. If they live nearby - MOOOOOOVVVVVVEEEEEE AWAY.
I don't think you need to require your husband to never see or speak to them again. He is to respect his parents. HOWEVER, if they continue to disrespect his wife and bad mouth you he should choose you over them and cut them off but that wouldn't be your issue or your decision since you will remain out of their lives completely. Chances are you might actually create a small peace this way because like Tweety needed Sylvester and Bugs Bunny needed Yosemite Sam, his mother needs you to justify her anger and gather the forces (her husband and son) against you. Removing yourself from the relationship means they can only complain about you a little bit longer before the contrast between their continuing anger/misery to your joy and happiness become wholly apparent to every one and your husband would rather be with you than them. Sociopath's love to accuse others of being the real threat and then taking of the role of the savior. They seem to be demanding you play the role of the black sheep of the family and, if and when, you simply walk away and deny taking on that role, they will rage with anger and victimhood but you'll be far away at a safe distance. They are not entitled to a relationship with you. You matter.
The internet is 90% complaining and entitlement and I hate it because I deserve better!
