It's all there in your words OP, you'd have to be
Recently we arranged a little break together, i booked and paid for an experience for us to do and she booked and paid for accommodation
Then I suggested something else I'd like to do, but she was vehement that wasn't going to happen, I was upset and annoyed at her attitude. I was really annoyed at the way she voiced her opinion, it was just a no.... at that point I thought we should meet up and have a chat but she ignore that request, so I decided not to send my half of the accommodation until we'd discussed it.
I asked to meet up to discuss our disagreement and moving forward. If we had met up and sorted our issues I would have paid straight away,
Another refusal to meet up
So i texted, I assume you've cancelled the accommodation and she didn't answer me.
Her next text told me that she hadn't cancelled the accommodation and was going to use it for herself and husband!!
Basically you turned what should have been a nice break together into a battle about an extra activity that she told you clearly she didn't want to do, you were offended she said no, and insisted you meet up to "discuss it further".. which she obviously had no interest in doing as she had given you her answer. You didn't pay her for the accommodation, so that made it clear you were not happy to proceed unless she agreed to the extra activity, so she decided to sack it off as a bad job, and go with her husband instead.
You also took her payment for the activity, cancelled it then didn't give her her money back, so you stole that money from her.
You can act perplexed all you like, but everything is right there, I'm amazed she is still giving you the time of day tbh.