Boston Dad in need of Help

[Teppo]

A close friend of mine said that I need to "fight for my marriage" by talking with her and asking her what I need to do to make her happy.

Also, this whole thing began on Easter Sunday when I confronted her with her EA partner in a park. I confronted them by texting her a photo of her and him with the caption "How romantic". She said "I embarrassed her professionally" since she showed him my text on the pretext that she didn't know what I was going to do.
I want to explain to her that I texted her the photo out of love and concern that she was doing something inappropriate, and that our M was in crisis. I really want her to know this.