One thing that helps me when I'm trying not to do something (eat pizza, phone T, have a 4th glass of wine) is to say that I can do that anytime I want - but I'm not going to do it right this minute. Yeah, I give myself permission to have pizza whenever I want, and as much as I want. But I'm just not going to have it right now. Maybe tomorrow I'll buy an entire pepperoni & mushroom one all for myself. But not right now. I'm good at procrastinating anyway, so this works for me.

If it becomes difficult not to text her, maybe you could look at it this way? And just put off texting until tomorrow ... over and over again? It's good that you've resolved not to text, but for the wrong reason I think. I don't think you're powerful enough to ruin her vacation. If you need the emotional release, take it. Seriously, she gave you permission. Think of it as a fire extinguisher hanging on the wall with a sign "Break glass in case of emergency." Use it if you really need it!