Fellas, if your new wife bursts into tears and says "Oh my god, I'm such a burden, you had to give up all hope of a happy marriage just to carry out your father's dying wish and rescue me!"
The correct response is "No, you don't understand, I do love you, my father's dying wish just gave me the opportunity to meet you and discover that love".
The correct response is not "No, don't apologise for making me give up on love, you should thank me for it instead"!
Honestly, the fact that they had that conversation completely changes the situation. It's not just Ophelia's self-doubt and trauma at play, here, it's the fact that Orpheus has never actually expressed personal interest in her to begin with. The fact that they keep insisting that him and Diana aren't a couple is almost irrelevant - as long as he's married to Ophelia, she will always feel as if she's standing in the way of his true love, whether that's with Diana, or anyone else. She's made it abundantly clear that she doesn't believe he loves her, and he has never even tried to correct her.
Think about this - the butler was able to look at Ophelia's behaviour, and deduce her true feelings, her intentions, and her plans. Even though he was one of the people in the mansion she tried her hardest to fool, he was still able to put it together. He's pretty sharp. And even he is fully convinced that Orpheus has no romantic feelings for Ophelia! The same goes for everyone else in the mansion. Long before Ophelia even began to act out, they all believed that their marriage was a formality, and the real lady of the house was Diana. And the reason is obvious: that's how he acts. However he might feel inside, he has always behaved far more comfortable, loving, and intimate with Diana, and quite formal, distant, and polite with Ophelia. What other conclusion could be drawn?
Ironically, the only person who has shown any awareness that Orpheus really does love Ophelia, and hasn't merely taken her in out of kindness and obligation, is Diana. And when she tried to say that, Orpheus stopped her and ended the conversation. At this point, if Orpheus actually has been in love with Ophelia this whole time, and just hasn't said so for whatever reason, I think that would make him an idiot, a coward, and everything will have been his fault. If he just hasn't realised his own feelings, then he'll still be an idiot, but at least this whole awful situation won't have been deliberately allowed to fester out of cowardice.