Originally Posted by Willravel

Trinity isn't Dexter, and I suspect Dexter's known that all along. Just like, as the smuggling and murdering couple laid on their final beds, covered in plastic wrap, Dexter was able to glean some enlightenment about the nature of coupling, Dexter is using the opportunity with Trinity to help him adapt and grow. Trinity isn't in control, he's not got the same kind of dark passenger, but he's made the family disguise/connection work for a very long time. Dexter can't really rely on Harry to learn how to be a father because Harry was more of an obsessed coach than anything else. In order to father normal, well adjusted kids, Dex needs to assimilate this serial-killing sociopath meets paternal provider and teacher skill-set.

Ultimately, these slowly developing skills are building Dexter into a better and more complete human being. Trinity will, in the end, have contributed to Dexter possibly overcoming the dark passenger. It's really fascinating.