Well, tragicbat, I have to say that you've changed my mind! Actually, your hypothesis is close to what I thought the very first time I watched this story. Quentin seemed perfectly nice, right up to the moment he carried Maggie over the threshold of the Great House--and then all hell broke loose.
Having an abusive and flagrantly unfaithful spouse would traumatize anybody. Probably the only bright spot in Quentin's first marriage was young Daniel. I'm sure Q's heart was in the right place when he gave Roger and Elizabeth a home at Collinwood and let Will and Carolyn live in the Old House for probably a token rent. He even gave Elizabeth the role of hostess after Angelique's death. But it only made most of them resent his wealth and what they saw as his absolute power over their lives. It's no wonder his closest relationships were with people outside the immediate family--his lawyer-cousin Chris (gone too soon) and his doctor friend Cyrus Longworth.
Anyway, what I'm getting at is that off in Europe, with Angelique (apparently) dead and away from all those negative stimuli, Quentin was free to be himself and woo and win Maggie. And I'm sure he thought that bringing her back to Collinwood would make everything better. Instead, things went from bad to worse, as Hoffman started her get-rid-of-Maggie campaign and especially with the return of Angelique. And it really did take Angelique's being really and truly dead, a corpse-littered stage and a burned-down mansion for Quentin and Maggie to find each other again. I always thought it was smart of them to go right back to Europe.
In my earlier post, I did forget to mention the all-too-brief appearance of Paula Laurence as Alexis and Angelique's aunt Hannah.