very cool homework, Mik!
I’m don’t opine on the matter of divorce and remarriage, having done so myself-I’ll just say that you can’t force a partner to honor the marriage contract when they are determined not to do so, and I don’t believe the other partner should forego the sacraments because of that.
My marriage to MrT5 was the second for both of us, we were married by a Catholic priest, and we went to Mass and received Holy Communion on a regular basis, for whatever that is worth-my faith in God remains unchanged, no matter what life has dealt.