It's written so that Jade and Stephen wanted to have a threesome with Isabella, but sex didn't happen.
Then Stephen Burke admitted that he tried Isabella again without Jade, but he himself says that sex didn't happen.
And ultimately in EP8 we see how Stephen Burke wants to arrange a date with Isabella.
That was it already. I know more too.
There is also Bella's inner monologue when she sleeps with MC after helping him clean up, where she says her feelings for him are making her become the one thing she hates:
isa "(I let my urges get the best of me. It's just carnal.)"
isa "(It's just carnal.)"
isa "(It has to be. I'm old enough to be his mother.)"
isa "(You read about these relationships with age gaps, you don't experience them yourself.)"
isa "(No, not a relationship. Adultery.)"
isa "(You're an adulteress.)"
isa "(You've become something you hate.)"
If she had an affair with Burke then her monologue would be different since she would have already cheated. The scene in the library with Burke and Jade doesn't have any dialogue we hear, but that may have been when they offered her the threesome and she demurred. Plus we see Bella shoot Burke down every time he approaches her about getting together one-on-one. She hates the idea of being in an adulterous relationship and that would be doubly so if she got busy with the married Burke.
