That was what I was given to understand. Father Manning (who I dearly loved) felt that divorce was a sin. The only references that I found to it in the Bible were that a man was not supposed to divorce his wife.
A friend of mine refuses to remarry to this day for that very reason. She feels that the Church would view her as an adulterer, but again I only found that in reference to man and not woman.
Father Donahue told me the same thing that you have. That it would not effect Matthew's legitimacy.
The Catholic Church does view you as an adulterer if you get divorced and then get remarried without an annulment. Marriage is a Sacrament, and cannot be "ended" by divorce.
Regarding the 15th station, I've read varying accounts of when and how it was added. Even the Holy See website only lists the 14. Since the Stations of the Cross are a devotional exercise, there are no set rules so to speak just tradition. There are various prayers online but I would think reflecting on what a given station represents and means to you is good- and I'm sure your priest/pastor/minister can suggest prayers.
The Aedicula of the Holy Sepulchre from where Jesus rose from the dead "And surely I am with you always, to the very end of the ages" (Mt 28,20)