sex with brother's girlfriend

I met my elder brother's girlfriend in the market, she said that your elder brother doesn't have the strength, I didn't understand anything, I asked what do you mean, she said you are the one who doesn't like having sex with brother, I felt very bad, his girlfriend said that I am going to leave your brother, I said don't do this, she said I can't keep you happy, so tell me how can I make you happy, she said that if I don't fuck your brother then you will have to do my work, so I chose her option so that my brother doesn't leave his girlfriend, she said brother I don't have the strength, you have the strength, so make me happy, so finally I had to have sex with her and she liked my sex so much that now she is telling me that whatever happens now I want to have sex with you every day, so now I have said yes for my brother.