My boyfriend cheated

I thought he was a very nice person. He is preparing for an exam in delhi. He is very intelligent. I once saw Tinder in his phone. He told he just made account their out of curiosity. He cheated on me last night. Today was a special day for both of us. We are in LDR from last 9 months. Everything was fine. Last night his friend called me and said he is cheating and he brought a girl with him. He sent me the photos too. I was devastated. In the morning I recieved several gifts he had send for the special day. I confronted him. He said to return all the gifts he and his mom have given which are worth 1 lakh plus. I came to know this is not the first time he is doing this deed. He uses tinder for all this. He promised me that he will do all this only after marriage with me. Yet he was doing all this behind my back with tinder girls. His mother does not know yet. Should I tell her? I am heartbroken. Also he was begging for continue the relatinship for 100 times but I again and again said no. So he started threatening that if I do not return the gifts by next week he will come to my home. He smokes weed and take some pills. I have seen his extreme mood swings so I do not really know whether he will fo this or not. He was ver possessive and has even beaten some boys behind my back. I thought it was love. His bhabhi is still telling me not to break up as he is a boy and boys do such stupid tjings but he really loves me. I know she is misguiding me. But she told me to not to tell his mother as she is a heart patient. Im so confused and sad. Please tell me what to do.