FWIW, I usually try to comfort myself with the thought that it seems exceptionally unlikely that just one wrong move could totally blow things. Especially something as minor as sending a friendly text. If she doesn't respond, then it was probably just a neutral move. You could experiment a bit and monitor results. The real challenge is you can't get your expectations up. Especially if she DOES respond, that's the tough part for me.
M: 42 H: 43 M: 8 years S7 and D4 H has D19 and S25 from previous M Bomb: 3/6/14 OW discovered, EA & PA 1st separation, 10 days, decided to reconcile & moved back in. Fail 2nd separation: 5/1/14