Classic manipulation in operation here. She clearly didn't want the kids to spend the night with you, so engineered a situation which pressurised your S to go to the grandparents. Then, of course, when you complained, it's your fault. See the pattern?
As for texting her, well, that was a bit of a no brainer really - you shouldn't have done it. I know it hurts that she's out like an alley cat, but, you should be trying to detach from the situation, acting as if nothing is bothering you. I know it's difficult. Whilst it is disrespectful, I doubt she'd even notice if you did the same.
I know you care, your her H, but she's sacked you from your responsibilities. She has to wear her own big girl pants. What would Clint do?
M 45 W 52 SD22 S9 D8 BD 6 April 2015 Not living together 4 Dec 2015