It is the duty of the husbond to give protection and maintenance to his wife.It is the duty of the wife towards her husbond to submit herself obediently to his authorityand to remain under his roof and protection.As a rule the wife is not entitled to separate residence and maintenance from her husbond.But Section 18 of Hindu Adoptions and Maintenace Act 1956 provides that under certain circumstances.Also Section 18(3)enumerates circumstances under which a Hindu wife shall not be entitled to separate residence and maintenance. they are
i.Unchastity,
ii.ceasing to be a Hindu by conversion.
Burden of proof lies on your father about her chastity( already married and living husbond at the time of your father marrying her)
She is not termed as Concubine. A Concubine is one where she is having living in relationship with a married person while his wife is alive.
