ESA and a visitor

Hello everyone, I am new here, hello everyone. I have a question - My fiancé is coming over from Italy for a while (I’m not sure how long), I am on ESA and PIP and have been for a number of years. She is going to stay with me in my tiny one bedroom flat. She will buy some occasional food shopping (not too I much, I insist because she is a guest). She has a house in Italy, and a bank account etc. She will not contribute to any bills they're all in my name and I will pay them. She did come out last year as I was having a major operation on my spine, I couldn’t have done without her, because it took me a long time to recuperate, and my family have all passed away, she was the only one I could ask for help. I was on strong doses of morphine and didn’t know where I was  most of the time. That time, I didn’t inform the DWP,  because I was in such a state about the operation. This time, I am having sleepless nights, because I worried that I will get caught, go to jail, lose my money etc.