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.
Teppo,
I'm struggling with my inner nice guy right now. He's telling me to shut-up and let it go. The nice guy is losing...
You can explain it to her, but you should probably use words that she'll clearly understand. Something along the lines of, "If the inappropriate relationship continues, then I'll lovingly kick you out on your @ss." And, if you have a suitcase or some boxes with you at the time, then that can help reinforce your loving message.
