Divorce on basis of past relationship

My close friend was in physical relationship with a married man at work place and later went to depression because of that and was on medication for a year. Post resigning from that job she got a proposal through close family,she disclosed about the relationship and the depression and she was on medication to him and sought emotional relationship more than physical relationship.He agreed to everything and stated he shall be there with my friend in all odds and take care of her.Post marriage he has been using stigmatizing my friend and constantly being said that my friend came from mental asylum by him and his cousins and now he is seeking divorce by blocking her in all modes and his parents demeaning her that she is a psycho and characterless. But my friend was loyal to him despite of him not being intimate with her even she didnt complain as she wanted more of emotional bonding. Few messages from his previous messages retrieved he also had various physical relationships and called them as sh*t , and few with a male friend in a way requesting oral multiple times.she got doubt and even she asked when my friend was with him whether he is bi se*ual In this case how can my friend deal with the allegations and proceed further legally