He didn’t say he didn’t love Marian. He said he loved someone else. Obvious implication, he’s fallen for Regina.
True, he could be in love with Marian, but Robin seems like the kind of guy who would choose to do “the honourable thing”, so I think that explains his marriage in the first place.
Even if Robin is in love with Marian and with someone else at the same time — and the implication is that he’s in love with Regina — this show has used misleading dialogue before. When David took his sword to Regina’s house (in early season 2?) to get Henry, Regina said “You won’t be using that”. David objected, and Regina said “I mean, you won’t need to use it”.
I think it’s important that the writers didn’t have Robin declare his love for Regina outright. That could be the solution to the Robin dilemma: nobody wins.
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