I understand your frustration. I’d be totally feeling frustrated, too. *hug*
I would talk to your FI about this. This is not just about the wedding, which is just one day. This is about the role of your faith in your lives for the next 50 or more years. I’m afraid the situation is deeper than you two may realize.
What does your FI think about the Church and her sacraments? Does he believe that the sacraments are gifts from God that will bestow special graces on the both of you? If he understands and values this, he will want the Sacrament of Matrimony.
Talk about how he feels about the believing and living the values of the Gospels. Does he? If he does, explain to him why studying the Scripture is important, and why the readings at Mass are important, and how they incorporate into the vows you two make at the altar.
Talk about how he envisions faith in your lives. Does he want to continue to nurture his relationship with God, and also, help you maintain yours? If so, the two of you will need a regular prayer life, and you two will need to pray together regularly.
How does he envision raising children in the faith? Remember that the home is the domestic church, which means that this is where your children will learn about love, faith, and God first and foremost. Catholic schools, priests and nuns, books, and CCD or other religion classes are only secondary sources.
I really applaud you for wanting to practice the Catholic faith. It’s hard on your own, not to mention, when the person you love the most isn’t into it or doesn’t desire to as much as you do. I invite you to try to nurture your prayer life together, go to retreats together, and continue to go to Mass and try to understand the Church, her sacraments, and teachings. It’ll be difficult as anything that’s different is going to be hard. But I believe that your desire to be close to God is a work of the Holy Spirit, and if you continue to work towards it, God will help you.
Best to you two.