Right now the only thing I'm curious about is what behaviors you are finding risky/unprotected. You said they are using condoms for sex and any toy use and that they are not having oral sex.
What of her behaviors with her boyfriend has you fearful that you'll get something from your shared partner with her?
Woodsmith: My husband
Merry: Tig's wife/slave
NT: Merry's boyfriend/owner
Elle: NT and Merry girlfriend
Umbra: Elle's Dom
Pet: Umbra's slave/wife, Elle girlfriend
Domo: Pet's submissive