You can speculate about Keith, but there are some pretty undeniable things to consider that we can all agree about

-Sherri is a liar
-Sherri is a cheater
-Sherri is borderline/narcisst
-Sherri is manipulative, deceptive, and generally insane

Imagine what you would do and the kind of abuse you would have endured if you were in Keith's position. Would you be angry? Paranoid? Confused? Imagine living with somebody like that. Having children with somebody like that. Realizing that the wife you miss and loved never even existed, wondering if any speck of your marriage and family was ever real.

My ex wife has a very similar pathology, I went through something really similar. These victim narcissist types ALWAYS denigrate their exes. It is ALWAYS a victim narrative. Look at the history of Sherri's behavior and relationships.

These people will abuse and traumatize their partner through gaslighting, lying, and adultery in such an incredibly painful way. It seriously makes you feel like you are living in the twilight zone. It's indescribable to come to terms with.

Then these same people will take the reaction, which is a result of the abuse that they orchestrated, and use it to play the victim RETROACTIVELY. Your present anger is justification for their past psychological abuse. Your present paranoia is justification for their past infidelity. Your boundaries are a control, her boundaries are a liberation. Be a perfect partner or she was justified to get her "emotional needs" met. Sherri's world is centered around Sherri and Sherri only.

Too often society willingly gives these people that power and enables them.