The misunderstands are extreme, and could probably have been resolved in better ways, but at the same time I can't blame them.
Ophelia's at fault for not listening to everybody, but do you expect her to believe people after she spends most of her life abused, and then when she's finally met somebody who she thinks likes her, everybody around her tells her that he loves another woman and scorn her? If you're raised in a negative environment, it's not exactly easy to believe somebody who says they love you when everybody else talks about the rumors, and assumptions against that.
Plus, at the end, yeah he's her fake lover, but he's also one of her few friends that she can actually talk to, and would you expect her to be alone? He's her friend, that's it, she doesn't want to be alone right now and she's just realized her efforts have all been useless. She's also not the most optimistic person, so clearly she'd go talk to somebody about it.
On the other hand, Orpheus is at fault for not stopping the servants for behaving in that manner towards her. However, he did try to tell her he didn't want to divorce her, or that it was a misunderstanding but there'd always be something that cut him off, or prevented him from saying everything. There was also his fear that she hated him because he wasn't of noble blood, which in that time, was probably a huge deal.
They both made mistakes, and are both to blame, I'm just hoping they get the chance to really talk it out at some point.
I love this story though! Thanks to the Scans Team for the updates! The art is beautiful, and the story despite the major drama is really interesting to watch. I love how their feelings are displayed strongly, and I can't wait to read more.