I’m so sorry you find yourself in such a difficult position. Your wife is struggling with the possibility of infertility. For many people, discovering they can’t bear a child is like a death. It is the death of the child they thought they would have. People are often not their best when they mourn, especially if they feel unsupported in their feelings of loss. What complicates your situation further is that your wife doesn’t really know if there is something to grieve. She is not going forward with testing for either of you. It may be that she is very scared that the results of such testing will confirm her worst fears. I understand that. But I also know that as long as she doesn’t get the testing, she is living in fear.
A great distraction from all of this is irrational jealousy toward your mother. Feeling out of control of her body, your wife may be trying to control you and your relationship to your family. Instead of embracing this new life and becoming part of the family, your wife is distancing from your new brother and your mother. What she doesn’t seem to understand is that by punishing you for talking with your mother, she is also putting distance between the two of you as. She is in danger of creating the thing she fears most: the loss of you as a partner and loss of the child she dreamed of having.
Love does not require sacrifice of your relationship with the mother who raised you. Love doesn’t ask people to choose between people they love. I can only suggest that you talk with great sympathy to your wife about your mutual concerns about fertility. This isn’t just her problem. As a married couple, you are both unable to create a baby. It might help for you to take the initiative and find out what testing involves. Then gently remind her that you two can begin to solve the problem only if you know what the problem really is. Do this in as loving a way as you know how. I hope she will be able to talk to you about her fears. I hope the two of you can become partners in addressing whatever might be the problem. Remind her that at only 22, you have lots of time to figure it out.
As far as your relationship with your mother and new brother: I don’t think you should give in to blackmail. I hope you can reassure your wife that you love her deeply but you can’t cut off your family when no one did anything purposely to hurt her. You can’t make her be kind to your mother, but you can tell her that you won’t stop talking with your mother and seeing her often. I hope your mother has the maturity to be patient with your wife.
If talking to her with kindness and understanding doesn’t work, you may need the help of an infertility specialist or therapist who specializes in loss. The two of you may need professional support to help you through this difficult time in your lives.
I wish you well.