I had a traditional Indian arranged marriage. My wife told me, after 4 years of marriage, that she is a lesbian and has been having an affair with my neighbour. I would divorce her, if not for our daughter. What should I do?
I know someone who is gay, homosexual, married and has a daughter. He married because of social and family pressure. Besides even today conservative families are not comfortable or open to these relationships. He loves his daughter, however has no feelings towards his wife. He never gives her time or attention. He superficially maintains the relationship or marriage just enough, so that his family doesn't have issues or question them. And yes, I know he has relationships with men. I don't know if his wife knows about his sexual orientation, however she is still committed to the marriage. You are in the exact same situation.
Now tell me, why do we expect women to accept, understand and make sacrifice to keep the relationship going? Why can't men do the same? She probably married for the same reasons that I mentioned.
If you are asking this question, then I'm going to assume that you don't communicate much anymore. Communication is the key. Talk to her and find a way to work things out. How attached is she to your daughter? Are you willing to have an open marriage? If you want to end the marriage, who gets the custody of the child? Alimony? How will it affect the child? Do you want a second marriage? Most importantly, is she willing to be bisexual for the sake of your marriage, society and daughter?
I've said this many times. I'm telling you the same. "Communication" is the key to any relationship. Talk to her. It's not that complicated.
Silver lining: She didn't marry you just to get a child from you. If that was the case, she could have filled for divorce and tried to get custody for the child along with alimony.
If she's with you then there is still a chance for you to work things out together. Though she may be with you due to social and family pressure.
Talk to her, be open minded and understanding when you do.