In most situations, "trial separations" are just an easier first step to letting go of each other. The couple isn't ready to let go of the "good past" in recognition of the "bad present." And after they've lived apart from each other for a while, one or both of them figure out they can, in fact, get along without one another. A lot of the resistance to breaking up permanently is the fear of being alone.
I'm really glad you were able to work it out. It sounds like both of you did a lot of necessary internal work, mostly on communications (the #1 killer of marriages, especially once the wife decides she's strong enough to stand on her own). In my experience, the wife works hard at changing, and the husband can't see any need for HIM to change...it was all HER fault in the first place!
I know I'm generalizing from personal experience. I mean, not all hubbies are major narcissists. (So guys, ya don't need to correct me.) It sounds like you very definitely have a good one. Any man willing to do that kind of work on himself is well worth hanging onto. I wish you both all the best.