My ex who got the house in our divorce, now has a live-in boyfriend. The house is large enough such that she has also rented the 2 upstairs bdrooms from time-to-time to various people. They are living "as a couple" but I'm fairly certain she would make that appear not to be the case if she knew I was attempting to end the alimony payments. Should I get a PI? What questions should I ask? I've read some recent articles that brought up examples such as grocery shopping together, working in the yard, etc... Thanks