This may sound harsh but IMHO, you shouldn't hide things from someone you intend to marry. That is a bad way to start a marriage. That said, it is best to communicate. You obviously have different priorities and I think those need to be discussed. You are right: money is one of the biggest problems in many marriages. I don't think you have to ask for permission but you do need to talk about expectations because once you're married, your money becomes "our" money.
Just because other people pay $6000 for one bag doesn't mean that it is a good argument for you to do so. In all honesty, $2000/year isn't exactly a small amount just on handbags. I know it is easy to get caught up and that you love them, but keep in mind that tPF spending and "real world" spending are totally different! Sit down, talk it over and see if you can reach a mutual decision.
What others are willing to or what they do spend on bags shouldn't be a concern when making your own budget. You need to do what is comfortable for you and your family. My only rule is that I have the money and that I never use a CC for a bag if I can't pay it off as soon as I recieve the bill. No paying it off in installments IMHO. No bag is worth debt.