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I am so sorry that you are having these problems with your wife. They are not due to anything that you have done, but are a result of some childhood trauma, perhaps neglect or abandonment.
She does not have bipolar disorder, but rather a personality disorder known as Borderline Personality Disorder (BPD).
Those with BPD tend to view their relationship partner as either idealized and wonderful, incapable of doing anything wrong, and then can change to seeing them as totally devalued and incapable of doing anything right.
They get very angry and they sulk a great deal as your wife is doing now. Living with these individuals is very trying and is like trying to walk on eggshells. There is nothing you can do except wait for her mood to change.
You have not caused this and her infertility does not cause it.
Going to a psychiatrist is not what she needs because he or she is likely to give your wife medications. She needs psychotherapy (talk therapy) instead, particularly Dialectical Behaviour Therapy (DBT).
Let me recommend some books that will clarify the issue and help you to manage this situation. They are availabe by post or can be electronically download from amazon.co.uk.
and this self-help book:
I do hope that this will help to heal her, and it will give you the knowledge and understanding to better able to adapt to her condition.
I shall keep you family in my prayers.
Elliott, MAE, LPCC, NCC, CCMHC