May, you get to make this decision (regarding the trip) and I can't help but feel all this thinking and waiting you and your H are doing - him wanting you to make a decision for him, you not wanting to make a decision for yourself until you know more about him - with the trip, with your work, with your marriage itself, is just another layer of denial.
Your H has done nothing about removing his mistress from his life decisively and strongly and committing to YOU as his wife, not the family package with children or the house or just 'not being the bad guy'. That is really not going to change in two weeks and even if he did it tomorrow, you'd be insane to believe him. So make your decision - whatever it is - on the FACT that your H is a lying cheater and either doesn't know what he wants and hasn't done in years, or isn't willing to tell the truth about what he wants as he thinks you might make life uncomfortable for him if he does.
Make your decisions about your career, your marriage and your holiday based on that.
Your decision might be 'I will wait a bit longer for this lying cheater to choose me' and 'I will move towards financial independence' and 'I will not go on the vacation and we will now be acting like cordial separated co-parents' or it might be something entirely different - you get to decide what that is. But I can't help but feel all the buck-passing and waiting that your H is inflicting on you - well, you are choosing it. There's literally nothing he can say or do or pull out of the bag in the next fortnight that is going to substantially change the truth about where you are in your marriage.
What other information do you need to make your decisions?
Edited to add: I guess what I am saying it, that I kind of agree with your H - the trip is an artificial deadline. Or at least it is if you inflict it on him rather than take it as one for yourself. He's very likely to tell you whatever you want to hear about ending it with his mistress so he can have what he wants - a happy family on the trip. And that means nothing, because as you know he will lie and cheat to get to have all of what he wants. A deadline is not artificial if you set it for yourself and you can make your decision today, tomorrow, in two years time or just the very second you are tired of the status quo.
