I've lost trust in my wife

I have been married to my wife for 3 years. We have a 1 year old and things are still kind of tough since this is our first child. Shes brought up divorce twice in our arguments and ive lost trust in her. How am I supposed to love my wife if I feel like that anytime she will leave? Thats why I said ive lost trust in her. Like my mind is telling me to put up a gaurd since this person may leave me at any moment. She will try to make physical contact with me by giving me a hug or holding my hand but all i can think about in my mind is "is she just playing and doesn't really love me"? I dont even feel sexuallly attracted to her ever since she told me this about a couple weeks ago. Like making love is something very intimate and why would I want to make love with someone who at any second would leave? Has anyone ever been through this? I dont even want to bring it up to her because each time i express how i feel it somehow gets turned around to me doing something or being the culprit.