I don't get the whole Rory-Logan-Odette love triangle...

I'm rewatching AYITL and I don't understand why Logan is marrying Odette. He and Rory are clearly still in love and he doesn't show any signs of being particularly emotionally attached to Odette, although granted we don't really see him with her. So I don't get it. He's not married to Odette, they don't have kids, if he wants to be with Rory then go be with Rory. Or is it because Odette is an heiress and his family expects him to marry her? It feels like the writers needed a reason that Rory and Logan can't be together so they just decided to turn it into an affair but the affair itself doesn't make a whole lot of sense to me