Verses to help us break the habit:
Beloved, do not believe every spirit, but test the spirits to see whether they are from God, for many false prophets have gone out into the world. 1 John 4:1
We destroy arguments and every lofty opinion raised against the knowledge of God, and take every thought captive to obey Christ, 2 Cor. 10:5
Death and life are in the power of the tongue, and those who love it will eat its fruits. Prov. 18:21
Love bears all things, believes all things, hopes all things, endures all things. 1 Cor. 13:7
If you are dealing with an emotionally/verbally abusive husband, please check out Nina Roesner's eCourse, Strength and Dignity for a lot of spiritual healing and tools to help you handle that situation well.
If you are truly not safe, and you have legitimate reasons to believe that the worst is happening (your husband is abusing you, he is having an affair, your family is facing a tragedy), please seek in-person, appropriate counsel. If you are not safe and need to contact the police, please do so.
When we talk about not assuming the worst, we are talking about not imagining that terrible things are wrong when they really aren't and not speaking death into our relationships. But if there really are things that are obviously wrong, my prayer is that each woman will have the wisdom she needs to handle that situation rightly. Not to ignore it or wish it away. But to address it properly.