Just on the off-chance that a passing solicitor sees this. My STBXH says he's living somewhere but all the evidence from what I know and our joint account bank statements tell me his is living with his OW. A P.I. told me he can trace the address he's at by using databases. Is this true?
He told me the place. His bank statements tell his every spending pattern in the area for each day since before and after he left. no hotel bills, no rent, he knows noone else in that area. he works miles away.
He has better sources of information than you do. I found a friend's address recently by doing a bit of detective work and a couple of searches of publicly available info on the net. Of course I could have just asked him but tracking him down was much more fun