Do adulterer father can get child custody

Hi All: My husband is having affair with his unmarried colleague and they declared to our family and his office. They declared they are in relationship and would not stop that and they do not need to be married so they do not care for me. He is staying permanently with her. He says i have no fault and hence he is not sending me off but he have strong feeling for her and cannot live with me anymore and wanted to live with her. They have not disclosed to her family who are in Mlore and we are in Blore. My in-laws are calm telling me to wait untill she leaves him by herself as it would be a sin to send her off and asking me I am free to take any decision if I am not ready to wait. Ours is love marriage with 12 years of relationship. We have a four yr old daughter. She is too much attached to him though she has talked with him on phone than spending time with him in person. He is calling daily only after his affair came to light. Before he never bother to spend time with her. I am unable to take any decision though I feel that I am not valued but having some hope that he loved me he would realise his mistake. what if I divorce considering the bitter situation now and not get any chance for reconciling at all in life. Incase, if he insist for divorce, my question is will he get my child custody by any chance. Profession wise also I am only earning (infact funding his business also). He has a business which is going under loss and have debt outside for more than 40 lakhs. So I hope I will only get child custody if things goes bad. Please confirm. Also i see other parent will have visiting rights to meet the child. What if I get a better job in other city or country? Just because he wanted to meet my daughter is there anything I should be in same city or India only??? Should I get any special permission or grant from court to re-locate??