I’m so sorry,
The answer is no you cannot trust her.
Not at all.
You have to understand some things.
Your marriage is over. Your wife destroyed it.
You cannot fix it. She has to fix it.
She has to want this marriage. She needs to fight for it. You need to protect yourself.
Rules need to be put in place. But you can’t be her jailer. She has to voluntarily accept them.
Also bad behavior needs consequences. She needs to see that one slip up of any kind and marriage is permanently over.
The first thing you need to do is contact a lawyer. You need to know what divorce will look like and if they can give you any advice on how to protect yourself.
Do that immediately as you can make a lot of big mistakes.
You don’t have to file but you need as much information as possible so you can make good decisions.
Don’t worry about saving the marriage yet. You are not out of the investigation phase. There is a lot you don’t know.
Highly recommend you get the book "Not Just Friends".
If you were in a university course on infidelity that is the text book they would hand you.
You’ll see a lot of the same things in it that we are saying to you.
Read it first. The. Make her read it. If she can’t be bothered then it’s over.
She needs to come clean. Fully clean. No more secrets.
Get the timeline and polygraph. Immediately.
They had a lot of opportunities for sex only once. Remember he is probably still lying to you to keep it from his wife.
You know why he stopped painting. His wife found out most likely.
I would contact that man’s wife. Tell her everything you know. Tell her you are considering divorcing your wife and you could use more info. Her hatred of your wife might give her incentive to dig further. She can be a valuable source of info.
Next contact that guy on the phones wife. Tell her everything. She may be able to tell you more.
Also it will show your wife there will be consequences for more "just a friends"
Tell the wife of the brother first then I would call your friend. Call the wife first because your friend might try to protect his brother. If he is a real friend he may come clean and tell you more.
I would frame it to him that you think she is a serial cheater and you think you should divorce but she is trying to save it. If he has a heart and is your friend he won’t want you hurt anymore.
I would also suggest if there is family near by to have your wife go stay with them for a while. She wants to be single give her a taste of what it’s like.
Maybe she likes it so your marriage should end.
She needs to see what she is going to lose.
And she needs to know your are real serious.
If she has good family I would notify them as well. Be careful who you notify on your side because they may eternally hate her.
Keep your side close.
Her side tell anyone and everyone you want.
People will tell you she needs to get into counseling. That’s true but you need to find one for her. Don’t let her chose. She will chose some open marriage, polyamory coddling counseling that doesn’t make her feel bad.
She needs someone who will hold her accountable.
Might I suggest you start with a "Gottman institute" counselor. They may be able to help if you go down that route.
Weekends are slow here. Others with more knowledge will come along.
Listen to the people here they know what they are talking about and have helped 1000’s of people.
This is going to be hard. It’s counterintuitive that taking steps to end your marriage might actually save it.
You have to be willing to walk away. She needs to be moving mountains to save this marriage.
She needs consequences. No more phone BS, no more "just a friend", no more uncomfortable flirting.
Don’t take it easy or it will just keep happening and eventually she will probably leave you.
I’m so sorry,
I wish you the best.