How difficullt it becomes when you know that your life partner can be move to other?

married 3 yrs ago,my husband is in merchant navy.we quarrel on trival issues,now he has reached to asking for Divorce,having 5 months baby girl.he is having girl friend (married) with whom he shares every thing,but not with me.now before some days i called to police becoz he beated me harshly I hot fractured in my hand.after that settlement took place.now he has joined his shio by saying that if I don't call u for months u file for divorce.he also goes to disco in ports