Unreal,
Thank you for replying and seeing where I am going with this. I bet a therapist started down this same path.
I imagine you are in the anger stage. It drives action and keeps back the depression.
Be aware the depression is coming later as a wave.
I was trying to get you to focus only on his betrayal and not on how his betrayal stacks up to how good or bad of a wife you were. That gets into comparisons which make you question "Why?" or "What did you do to deserve this?" You did nothing to deserve him cheating on you. As you know, the affair was about him, not you.
His act alone is enough to divorce him over, but imagine having the audacity to then lie to me WHILE being so reactive and abusive to me about lying?
Yet, you are doing things correctly and working through counseling so you can establish boundaries and get to an amicable relationship at a minimum.
You have kids together. That means that he will never be entirely out of your life.
The MC should be about building a way to work through fights and anger without letting them digress to just screaming at each other.
Now, to the real meat of the issue. You need to forgive your sister. You are angry and if she reported him to the police and things were illegal, she would have to press charges. I have tried to help someone do this and if they don't want to press charges, nothing happens.
You would just get your husband in holding for a day or so, if things fizzled and CPS called on you. Your kids will most likely be taken to foster care during the review, but I don't know anymore due to covid. FYI - I know all this because of past experience, not conjecture on how the law works.
Lots of people on here are trying to Knight in Shining Armor(KISA) your sister. She is an adult NOW and your parents should have protected her back when they found out. You can't punish him with the law without it having blow back onto you and your family.
Now, divorce, is a totally viable option. You are doing what everyone suggests which is consult a lawyer and file if the WS doesn't wake up out of the fog.
Sadly, this is like someone else on here, whose wife cheated 25 years earlier and he couldn't really punish her for it now. It was more about him getting past the situation and decide if he stayed or left.
So, lets talk about what you can get out of MC. You need to use that to get you past the anger and depression stages. It is to help you come to a decision to leave or stay based on your past marriage. Any way you slice it, don't go for blood because even in a divorce you want him to keep working and paying child support or alimony. You also want him to co-parent.
Please realize, I am not trying to get you to forgive him, but more to get to a place where anger is fueling every one of your decisions. Trust me, I have been there.
Usually people recommend the 360 and setting of boundaries. Read those and consider maybe detaching for a short time from your husband to clear you head.
To everyone who is commenting to me. This is about Unreal and not you. You advise to report/lock up her husband, would only hurt her and her family. Especially with a victim who refuses to report the incident or press charges. So, if you are going to respond, let her know how you plan on getting around that major roadblock, instead of keep guiding her towards it.