HMM.

Im assuming your Dad has been loyal to the relationship himself.

Skip the blackmail. You dont want what becomes of that.

My Grandmother had many sayings, and to this I say to you,



"When you pursue the path of revenge, dig two graves".



Trust is built on Honesty, integrity, reliability and loyality.

This is what happens when you abuse one of those. People will get angry people will get hurt, and things can get out of control.

I would just go somewhere away from the house with my Dad and the pictures and have a quiet talk. Hopefully you know your Dad well and know how to lead the conversation instead of just throwing some photos down.

So just tell him you have some concerns, some things are bothering you and you need to talk, and do this without her knowing.

Your Dad will probably become angry right away and want to react when he sees the pictures.

Tell him it is important to just think it out for several days with a level head and not to react with anger in the moment.

If he is unwilling to forgive her or not trust her again then he needs to quietly go see an attorney.

Dragging out a big fight will solve nothing when the trust has been broken. No amount of arguing, name calling, etc will take that back .
He has to conserve his energy and use it wisely and think it out.

If he is unwilling to take her back this is the importance of meeting with an attorney before she can make financial impacts that will affect you and your Dad. This is very important.


Take care.