This may be a point where you need to seek legal advice regarding your M and financial disposition. Trying to stop her from selling the house may push her to be more aggressive with divorce.
A lawyer might be able to tell you if you need to legally separate or whether you can buy her out of the home and have her file what is known in western laws as a "quit claim" which means you would own the home outright and she would have no further financial claim to it, even if the two of you do not divorce.
Anyhow, seek the advice of a lawyer and proceed as advises, although you could simply let your W know that you are not sure how to proceed with the house at this time and will consider her desire to sell.
Once you've said that, we often find the WAS drops a topic if we don't resist it.
