Try this: If they bring up that supervised visits are the law, you can say, no, they are not, but I am very happy to have you along . We are going to my place today to play piano and do some cooking in the kitchen, I think you will enjoy it as well!
I think W is scared you will take S and leave country. It just occurred to me. I would ,actually, bet 100% that this is the case.
As for the family thing-well, you (this is blunt) are not a family anymore and she may just see it as spiteful on your part trying for shared custody. All you can do in this instance is continue your 180s and love S every chance you get.
Moneywise- if it comes up, just say your son is always your priority or something to that effect
. We are going to my place today to play piano and do some cooking in the kitchen, I think you will enjoy it as well!