In America, based on advice from a relationship class I took in college for general degree requirement credits, my wife (Taiwanese) and I (American) set up three accounts. We each had our own personal account and one joint account.
Everything needed to pay bills and expenses would go into the joint account. This was the main checking account and we used it to send out rent payments and to make payments to other budgeted expenses.
After subtracting the money that went into the joint account for budgeted expenses and subtracting money that went into various budgeted investments and savings (joint investment funds, emergency savings, etc.), we each put an amount of money into our personal accounts.
The money in our personal accounts was for us to spend on anything we wanted. We had no say what the other person did with that money. The purpose was to avoid the number one cause of arguments in families: money. If blew several hundred bucks on a Treo smartphone, I didn't want to hear about it. Similarly, if she wanted to buy more over-priced cosmetics that served purposes mysterious to me, fine, go ahead, as long as you have the money in your account, you don't have to convince me that you need it.
A close friend of mine, who is Japanese-American (his wife is Japanese), didn't agree. He felt that a married couple jointly-owned everything and should not need to separate accounts like this. I've talked to others, from a variety of cultural backgrounds, who feel similarly. They tend to be the same folks that find premarital agreements abhorrent. I don't share this world view, but I did stop the multiple and separate account scheme.
Eventually, I found that our finances were becoming too complicated given our income. Too many bank accounts, money market accounts, etc. Eventually, we merged many of our accounts. Having separate accounts didn't stop all arguments about money. You'll still have them...after all, how much to save? What are you saving for? Are daily international calls to your mother a budgetable expense for the joint account or something that should come out of your account? Do you buy a used or a new car, what model? Etc.
We didn't have more arguments after merging the accounts. Just less paperwork.
When we moved to Taiwan, my wife came several months before I did as I was finishing up a project in New York. She opened up a bank account and transferred money to it. When I came to Taiwan, we looked into making it a joint account, which is a very simple process in the United States. But in Taiwan, they don't seem to have such a thing. And this was the local branch of HSBC telling us this, not some small, local bank.
In practice, however, it doesn't matter, I still have an ATM card for the account. I just don't have any legal rights to the money if my wife were to change the PIN number and on-line password. Currently, I am not working full time, but I do some substitute work for friends and acquaintances. Some buxibans require you have a bank account to get paid. I just have them deposit the money into my wife's account. I must say that I actually like letting my wife manage that account. She's better than me at managing the payments and monitoring accounts for deposits and stuff. I really don't enjoy reconciling accounts. :-)
Regarding the comment above about sending money to relatives as a type of extortion often inflicted on foreign spouses. That is very misleading. It is very common for Taiwanese to send money to their parents (and, really, not only Taiwanese). Also, it is too easy to say that you should discuss this before you marry. I think everyone should have a prenup before they marry, but even with a prenup drafted by the most brilliant of matrimonial attorneys, you are not going to be able to cover every situation that will come up in a marriage, especially a multicultural marriage.
Maybe your wife an you should try the multiple account approach. It may work for you better than I, especially in the beginning while your wife has trust issues. She should realize that making you totally vulnerable so that she feels more secure is unfair. There are numerous financial arrangements you can come to that will protect both of your interests so you can stop worrying about money and focus on building trust in your relationship. An accountant should be able to help you with this.
As for money demanded by her parents, well, you need to come to an agreement with your wife on this. I don't have a problem given money to my in-laws because they have helped my wife and I out on many occasions. What comes around goes around. Also, my mother-in-law is very good with money. I've also had to put up with more than money issues, as we've had in-laws live with us for extended periods (but also vice versa), and all the other challenges that come-up when you join with another family.
I have, however, turned down requests from people on my side of the family when I felt they've been living irresponsibly and that my giving them money would only empower them to continue doing so for a longer period of time. If you feel that is the case, you might have to make a difficult decision that your wife is not emotionally ready to make.
If it is just a matter of saving for your future, then you may have a cultural difference to deal with. Some families, especially in Taiwan, see sharing the wealth and supporting others in the family as the most important investment you can make towards your futures and, to some degree, they may have a point. This is the case in many cultures, not just Taiwan. Who's going to support your family if tragedy strikes? I don't envy the position you are in.
Personally, I have no problem being perceived as an asshole when I need to say "no" to protect my and my family's interests. But when I'm able, I feel I should help out when I can, when it isn't encouraging destructive behavior. I can be card to draw the line in both instances. I feel fortunate that I haven't missed the mark by too much in the ten years I've been married and I wish you the best of luck with your aim.