我因为未婚夫对婚前协议的要求而取消了婚约，我这样做错了吗？

NTA.

First off,  I'm sorry you're having to experience this, at least from an emotional standpoint. It can't be easy, but to be honest your stance towards the prenuptial sounded reasonable and, if anything, overly generous to his kiddo (imho).

Anyhow, It sounds like he's showing his true colors, and it's fortunate they were on display prior to marrying him. If he helped you build the business venture, it'd be one thing...but he didn't. Now he's throwing a tantrum because he wants a one-way contract that only benefits his own kid?! Oof.

Marriage, at least on the legal side of things, is a contract. Would you entertain a lopsided contract related to your business? Why would (or should) it be different in your private life, when you and your children's financial wellbeing is being negotiated?

It isn't you showing your true colours -- it's him. You have been very up front and very honest about your financial goals and intentions. You have also been very generous in your offers for his grown child who has two parents.

I have an RESP for my kid and a good life insurance policy that will take care of her in the event of something going wrong. In the event of a second marriage, I would expect a prenuptial agreement that would protect those things for my daughter. If it is an issue, then that is not the guy for me.

His daughter has a mom: a successful one who is capable of providing for her future the way you are for your children. He IS the one with the lack of things to offer his daughter: You are not there to make up for his lack of assets. Perhaps reassessing this relationship is VERY necessary.

Without knowing the details of the negotiations and the pre-nup itself, it is hard to really comment meaningfully or take sides. Maybe you were a total B about it, or maybe just so business focused it made him uncomfortable. Or perhaps he is trying to get more from you than he deserves.

Mind you the 2 main things couples argue about are sex and money. Money should be simple.

In the US most states have mutual property laws, which means that all money and assets belong to both people. That means pre-nups are important, and are supported by the courts. In many other countries the process is far more complicated. In the UK, your partner, on being divorced, should be allowed to maintain the lifestyle they enjoyed at your expense, while in Australia financial resources are split up based on how much each person contributed, individual needs, and so on.

Anyway,


You have no financial responsibility to his daughter, even in a relationship, and should the relationship end, and you have given her shares, you may not even be allowed to contact her, but she still owns part of your company
You have already been pressured to financially contribute to his daughter, which maybe you shouldn't do, and it should be his responsibility, while you would be better off with one offs, like phones, holidays etc
Pre-nups should be simple


Everything you own before the relationship is yours, everything they own before the relationship is there's
Anything you do with your business is yours, and their own income or business is there's
There is no responsibility for children or family of the other person unless adoption occurs (which you might choose to do later)
Caveats include


Contributions to a business or work should be factored in, such as you working 12 hours a day 7 days a week on your business, while he helps you without pay, means he is owed something, or even if he maintains the home, cooks meals, while you work, then he is owed something
It changes if you and he have children together




But basically, if you can't settle the financials, then there will always be resentment. Doesn't even matter whose fault it is.