I (23M) lost my girlfriend (21F) because of my sister (16F)

I (23M) lost my girlfriend (21F) because of my sister (16F) and I don’t know what to do.<br><br>My girlfriend and I have been dating for two years and have been very happy together. I have a sister who is 16 and she is very pretty for her age. She has never gotten along with my girlfriend and my girlfriend has never liked her.<br><br>The problem came when my girlfriend and I bought our first apartment together. It was a very expensive apartment and my girlfriend wanted us to live alone, just the two of us, but I wanted my sister to come with us because our parents are going through a separation and it would be better for her to live with me.<br><br>My girlfriend insisted that she wanted to live alone, but I told her no and she said that she would live alone and that I could live with my sister. I was not willing to leave my girlfriend alone so I went with my sister.<br><br>My girlfriend doesn't like my sister and has never liked her because she is very pretty and has a lot of male attention. She gets jealous of my sister very easily and I have had to talk to her several times to make her see that she is my sister and I love her like a sister.<br><br>I am very wrong. I bought an apartment with my girlfriend and now we are not living together. My girlfriend thinks I am stupid for choosing my sister over her and I don't know what to say to make her see that my sister needs me right now.<br><br>I don't know what to do with my girlfriend and my sister. I love my girlfriend and my sister very much and I don't want to hurt either of them.<br><br>My parents are going through a separation and I have to take care of my sister. I don't want to lose my girlfriend but I don't want to lose my sister either.<br><br>I don't know what to do with my girlfriend and my sister. Please help me.