Ha, not interested?
Chris and Stacia could barely be in the same scene together without her trying to get him to ruin his marriage OR with Chris drooling over her outfit or the way her skin smelled or some other aspect of her outfit/appearance.
So Chris had no issues gawking at Stacia clothes/unclothed (which she often is) while in a relationship with Tanya is in full swing so I doubt he has stopped leering at her.
Chris felt jealous on multiple occasions when Stacia started “paying attention“ to Declan.
Stacia decided to “move on” as you say when Chris literally had children with Tanya so it’s not that her interest has diminished it’s that she realized that the man of her dreams, her number one choice to grow old together….is out of reach.
So Declan is her second choice.
Sort of a
“I might as well be with that incredibly powerful witch if I can’t be with the man I’ve loved for years” kind of thing. Chris is the one that got away and always will be in her mind.
Maybe I’m just touchy but if I was in Declan’s place than knowing all of that about my SO would bother me and I think it would bother anyone ESPECIALLY because Chris and Stacia are constantly around each other.
Especially since Stacia seems to think that Chris would by in the right to cheat on Tanya with her. She hardly seems like the faithful sort.