Child custody

I m married from 11 yrs my kids are 5.5 yrs age .me and my husband living together I m house wife and he is working in pharma company after kids age 1 yrs my husband behavior got change and he angry on me every small small things and start hitting me sometime he trying to hit my head in wall he push my neck in this situation from last one year I came closer to one of my friend and we r in one relationship not physically but only on call ...my husband come to know about this one day and are family compromise and we start living together but I was in contact with that guy again after 3 month he come to know and he fight with me still we together that guy is not in my life now anymore ...I HV agreed that he was my mistake and I want my family but now a day my husband every second day tourcher me and fight with me he hit me like anything he abuse me and my family but bcoz of kids I m not able left him I want my kids bcoz they r only my strength..I come to know that my husband going to case me about cheating him Plz help me in this case how can I get my child custody ...they are the only my life saver and bcoz of them only I m here with my husband Plz help me in this ...if he case on me about cheating so is there any possibility that I ll not get my child custody..... Plz tell me what to do now till the time I HV not file any police complaint about him .....plz help me what to do