Just be careful, do all pre-checks, have a lodgers agreement in place, do an inventory, and always take a deposit at all times, do not make exceptions for anyone. I had a lodger stay me with over the last 6 months. It was the forth time that she had stayed with me, and the final month in my home, she was an unexpected nightmare. So be careful.
If I had the choice - I would rather keep my home to myself, and that is what I have decided to do now.
My advice to you is to proceed with caution, perhaps downsizing might be a good idea?