In the absence of any information from her as to what is going on, you really only have two choices - force the issue or try your best to ignore it.

As someone else here said, just asking a simple question "do you still love me?" is a good one to go with, however I'd be more inclined to get straight to the point and ask the obvious one "do you still want to be married to me or do you just want me to go?"

Do not accept her walking away without responding as an answer and even go to the extent of saying to her if she does, that this is all the answer you need and you'll start speaking to lawyers tomorrow as you can no longer live like this.

As things stand, you can't keep living like this and she is not going to offer any solutions, or even hint at what is wrong, then your only recourse is to default to looking out for yourself and take action to keep you happy.

Whether that happiness is found with her in your life or her out of it is something that you may have to seriously address.

Wish I had the time to do the sort of research u/ebbie45 does.