To sum the answer to your first question, she has been less than faithful and honest. There is reason to doubt it, but I'm not putting that issue at the forefront. Why I'm with her isn't the purpose of this post.

Her and her sister aren't very close, so if her sister was complaining then she would have said that as an annoyance. There's no other family attending, like I said, their family is pretty disjointed. I'm not asking if why she needs an answer is suspicious, I'm asking if there's something with the information I've been given and the alternatives I've suggested are out of line or if there's something obvious I'm missing.

I'm not resentful about going at all, I'd be more than willing to go. I'm just saying that I'm being asked to do something with urgency in which my circumstances can't determine an answer until the time I gave for someone that I've never met and neither of them have had any intention of introducing me or even keeping up with each other. I'm perfectly fine with going, even to pay my way if I can eventually afford it, but if she needs an answer now then I can't give t to her because I don't have an answer. The suggestions I made for her to pay for just the hotel were suggestions to get a definite answer, not that I'm expecting her to pay my way even though I'd pay hers if I were in her shoes and it would be not an issue.

I think you're completely misreading this because your post seems to be accusatory of things that I don't feel like me being resentful or unfair. To be honest if the whole picture was in front of you of what our relationship is, it would be obvious how unbalanced it is in her favor and our therapist as said as such, so I don't need an opinion on that, but again that's not the issue I'm here for.