As much as she's been helping Ren with her troubles, looks like Matsuri has more of her own still hidden...
And rather big ones, as we've now seen...
I guess that's why she got divorced and lost custody of her child, and can't go back home because her family disowned her. And maybe her needing a lot of money is related to that.
I was thinking whether or not the author could make Matsuri mostly innocent, though made a scapegoat by someone else... But it wouldn't really fit the story, would it? A big theme I'm seeing is unconditional acceptance, it's the main reason Ren feels comfortable around Matsuri (and nobody else) and while they offered it back, the news might make them at least demand an explanation (if anything, just to they can be on the same page about things). Matsuri being innocent or framed would work pretty strongly against that theme...