Separation

I am 52 years old, diabetic & a heart patient & unemployed since 2018 November when I lost my job in Saudi Arabia. In India I am not getting a job because of my age. My wife & I currently are not on good terms, upto 3rd November she was talking to me, then she along with the children left for her native place, 19th November they came back to Mumbai & from 20 November she has stopped talking to me, making black faces & not answering, can I get separation from her, but not divorce? I had an affair with her sister, in 2009 the whole family came to know, but there is no proof of the affair, my wife has forgiven her sister, but not me. I have 1 bhk in panvel which is rented out, which I purchased while I was working in Saudi Arabia, I have put my wife's name in the agreement, also I have a 1rk in Nerul where we are currently leaving. We got married in January 1994, my daughter is a dentist & just started her internship from January 1st 2021, my son is in 10th grade. I am getting 6000 from the rented house & 5000 from post office mis. So tell me what should I do.