Dear G,
I will not attend your wedding because you are a Catholic but choose not to marry in the Church as Catholics are obliged to do. I am sad to see that you no longer acknowledge Jesus as you did when you practiced the faith. We make choices and are responsible for their outcome. Your choice to formally distance yourself from the Church at this momentous occasion means that I, your uncle a priest, must also choose sides. I will always choose Jesus and His Church.
The ceremony you will be celebrating is a merely secular one. There are no sacramental blessings exchanged because the marriage will not be valid in the eyes of God and His Church. Legally, yes, you will have entered a contractual relationship that can also be legally revoked. A valid sacramental marriage can never be revoked because it forms a family bond by God, and what God joins cannot be separated.
When does one cease being a Catholic? Short answer: never. You will bear the mark of baptism on your soul, in this life and throughout eternity to follow. Catholicism was bestowed by the Church and your family with great care, a precious gift all hoped you would treasure. And even if you choose to deny your identity in Christ through heresy, apostasy or schism, you will always be a Catholic--and not just in name only. That excuse favored by politicians means nothing else than that you no longer practice what you are.
Your actions as a baptized and formerly practicing Catholic will be judged by a different standard than those of an unbeliever, because as much has been entrusted to you, much will be required. God formally adopted you into His family of believers; He received you as His daughter and not just as His creature. With this formal rejection of the Church’s blessing, you also choose to distance yourself from your heavenly Father. God may respect your free will, although like any other sin, it pains Him to do so.
Your choice misses the mark. The state will recognize your wedding, and to the extent that the state does so, they will bless it with tax write-offs and lower utility bills. But marrying by the state is like any other secular enterprise, done so only for recognition by society. You will go through life as Mr. and Mrs., but as a formal means of address only. The bond you establish can also be readily removed by the state through divorce or a declaration of annulment. What matters most, that God approves of your new family, will be sadly lacking divine love at its core. And I, as an official minister of the Church, will not be free to attend because I represent the Church you are publicly disavowing.
There is still time to change your choice! That is why I am writing you this letter. In hopes that you return to your faith and wholeheartedly embrace a new form of love that could be yours. Why settle for less when something much more perfect is readily within your grasp?
Your Loving Uncle, Fr. Jon
P.S. Please know that when you do choose to have your marriage blessed in the Church, I will be there for you.
I share your pain having experienced this in my own family. Many prayers coming your way and for your niece.
Oh Father, that is heart breaking for you I'm sure. It is never easy when family members turn their back on the faith. I'm going to offer a Hail Mary now, that your niece may return back to the faith.