Successful relationships are built on trust and respect. If you have a firm sense of where you each stand, then things flow without negative assumptions, like your first line of thought.. that she was too busy to respond, no biggie.
Trouble happens with a sense of rejection. Or your "bulls!t" meter going off. If it's an issue and money is a problem of hers, call her hotel or email and deal with it directly. Is it a tempest in a teapot or more? If you're feeling uneasy about what she may be doing, it comes down to trust.
So.. look at your actions, rather than hers.. and figure out what truly bothered you. If it comes down to blaming her, reword stating how her actions effected you.
It's not about making excuses for the other spouse, it's about learning to stand on your own two feet and taking accountability for your actions.
Thanks Gypsy, that's a really useful post. It's a combination of things, I think. I'm angry with her because I think her behaviour was rude (despite everybody on here apparently thinking it's normal) and, no, I don't trust her much. I don't want to get hurt again and I'm more than happy to knock it on the head right now. It was a bad idea anyway.