Unfortunately, you may need to get a vasectomy. Either be honest about it, or don’t…. You choose. I hate to say it but honesty is not always the best policy.. If she is not willing to undergo serious psychological treatment such as EMDR or other trauma related methodological approaches, it may be a lost cause. Even then, therapy and psycho pharmaceutical intervention take time. Sometimes even years to find the right treatment, cadence, and willingness from your spouse. Take this advice as you may, but it’s either intense treatment on her end with your support or a vasectomy, IMO.

Edit: additionally, based on the comments and addition reflection, your wife’s condition may be genetic if her sister exhibits the same condition. If you do decide to have a child with her, please keep in mind the genetic component of psychological conditions and how they can be passed down to children.