He lied to stay out of an argument. It would have been best if he was totally honest, and not about just that, about everything. You are old enough to be discerning marriage and having a partner not willing to share what’s going on with him is very concerning.
And how should I counter his argument of Catholicism being nothing more than a part of his “Maltese identity”? There’s no counter argument. We all are free to choose if we want to be Catholic or not. It’s up to you what you want to do with the information.
I grew up in a non-believing household. God wasn’t in the equation and one parent was alcoholic. God in his mercy (and the prayers of Catholics asking for the conversion of sinners) plugged me into the power of God. I came into the Church and the sacraments. I married a practicing Catholic man, my St. Joseph.** I wish I could tell everyone that the 2 households are polar opposites. One was darkness and hopelessness, the other full of light and God’s presence. A Catholic man will honor his marriage, his commitments, his wife and family. When hard times come, he’ll be on his knees before the throne of God. He’ll bring blessing into his marriage, his family, his neighborhood and workplace. He’ll honor and cherish you all the days of his life, because he’s plugged into the power of God. Difficult situations can turn around because he’s a man of God.
**
Don’t settle for less than that. Together with a believing Catholic man, you can have a wonderful life together and *come together *holding hands when you come before God to give an account for your life. Strive to come into what God has prepared for you and trust in His love and goodness. Time to leave behind what you knew when you were 10, time to come into His fullness as an adult daughter of God. Come into His blessing!