IIRC she wouldn't be in need of money if they got divorced. What if Harry gets another woman pregnant if they're not married? Fuck him, simple as that.
But now she can be blackmailed only because they haven't still got divorced and cut their ties once and for all.. I mean, the MC has finally succeeded in kicking Harry away from Evelyn.. why are they still married? why is there such a problem at all?
And regarding the next steps for the Evelyn path and whether to continue with a (maybe) boring classic harem game, there are other ways to deal with that. However exposing a goddess to being fucked by other men than the MC is blasphemy
, even if you have an alternative path. Although this sex stuff would happen willingly from the MC's perspective in the PS route, it wouldn't be too different from NTR and every time I have to deal with NTR, I end up deleting the game.