I've been wondering about this subject as well. Although, not an Orthodox source, I've found some of the explanations on this site informative and mind-boggling: http://www.jewishencyclopedia.com/articles/12340-preexistence-of-the-soul
The concept of the soul as a separate component of one's person is a Greek and/or Persian concept which eventually penetrated Jewish thought.
I find the original Judaic concept of the the soul as being the breath of life much more holistic with the teaching that God did not intend for death to occur when he created man, and that the split between the body and soul is a tragic consequence of sin. Therefore, I would say the soul is more of a sleeve torn off the shirt, rather than the blueprint of the shirt. That is why, after the Last Judgement, the soul and the body will be reunited, and mankind will be recreated (?). It seems more reasonable to believe that the soul is not the complete person on it's own, nor is it a reflection of the person as they were in their mortal life given that we look forward to the resurrection of the dead, not to the nebulous state the soul may find itself immediately after death.
Greek philosophical thought as well as modern expressions of the nature of the soul describe the soul as the real person (or the essence of the person), and the rest of the body is a husk. I personally hate this idea because it comes really close to crossing into the realm of modern psycho babble and maybe even being disproven by science (like someone gets clunked on the head and their entire personality changes). However, it seems like it is adopted later on in the Bible, so perhaps the Greeks and Persians had the correct view after all. IDK.
I realize my thinking may not yet be in line with Orthodoxy (and frankly my conversion has already taken more than a year, despite having regular meetings with my priest). However, I really like the old Judaic concept of the soul being a life force bestowed by God. It is not one's rationality, or thought, or personality. Those are physical traits determined by biochemical processes in the brain. The soul is much more.
Also, why do we think life begins at conception?
"The word of the Lord came to me, saying,
Before I formed you in the womb I knew you,
before you were born I set you apart;
I appointed you as a prophet to the nations.” (Jeremiah 1:4)
P.S. Also please tell your husband his Collective Soul idea is like a Runaway Train, Never Going Back, Wrong Way on a One Way Track.