Where do I stand?

I am married with 2 children and currently living in the UK. Recently I have been in a relationship with another woman and have decided that it is her who I want to be with. The main problem being the person I want to be with lives in Australia. After telling my wife that i planned to leaave her and move there to be with this other woman she assured me that if I did she would do all she could to make sure I never got to see my children again. I understand the prcedures to a certain point and know what i need to do. My main concern though now is will living on the other side of the world with another woman affect my rights or become a factor in any decision made by the courts even if i can make the comitment that I am willing to do all I can to make sure I can travel back as often as I am allowed to see them.

Thanks in advance for any help.