Marcel didn't need anyone to tell him that if he didn't step up his game real soon, he might lose Arianna in the process of keeping her to his side. At that moment, she saw him as no less than the moment he was.
He had to show her that monsters were capable of loving too - even if that means snatching her from her one true love, Elijah. Horrible right? But then, he was a villain and that was what villains did, snatching beautiful damsels from the good girls. Only that in this case, Elijah wasn't a good girl either.
In one word, you could say it was two bad guys playing off each other with the end prize being Arianna. And before you judge him, do remember that all is fair in love and war.
Thus, at that moment, Marcel decided on the woman he was going to spend the rest of his life with. Perhaps he had been lying to himself - and her as well - because even if Elijah returned his shipment tomorrow, there was no way Arianna was going to him.
