I agree with your statement of what the Church teaches with regard to marriage, but the Greek in +Paul doesn't really go into that. The reason I mentioned what I understand to be the actual meaning of the Greek is to point out that difference between the active Greek word and the passive English translation may be telling. In the first instance the wife departs from her husband, in the second, she is separated from him. Actually the passive would seem, at first blush, to support the Church's position, but perhaps the active voice better explains the Church's attitude on compassionate correction in the face of sin which has destroyed a spiritual union.
I would ask you to elaborate on this because it is not exactly clear to me how you came to that conclusion. What you are saying is that the wife departs from versus separated from somehow brings compassion into the first and not into the second?
I think the comapssion is the way of life for the Church regardless of grammar. The sinners are seen as sick, fallen, who are in need of spiritual healing and medicine regardless of the sin.
The difference between spiritual and legalistic breakage of the bond is pronounced and clear. When we say "divorce" it means legal devorce. There is nothing in the NT to support this. In Mt 5:32 Jesus dismisses the OT Jewish practice of giving a certificate of divorce because the Church does not recognize legal divorce. The only legal divorce is death of one spouse as far as the Churhc is concerned.