Of course not. Denominations, and in this case the Catholic Church all have their own polity, church resolution, statements of belief and in some cases theological doctrine. Salvation is based on faith in Christ and has really nothing to do with your church or any church. You are saved by faith alone, not by any other means including; church attendance, confirmation, taking the eucharist, taking communion, being baptised in water, being baptized in the Spirit, adherence to church rules, following church doctrine, tithing, or any other method of qualifying salvation. "For by grace are ye saved through faith; and that not of yourselves: it is the gift of God: Not of works, lest any man should boast. Ephesians 2:8-9
The responsibility of any church is to bring people to Christ and then to steer them to follow Christ. Of course the pastors or priests provide a suitable facility to gather together, administer the sacraments, teach the Word, perform marriages, baptize people, christen babies, anoint the sick, pray for the people, visit the homeless, visit prisoners, start ministries to help people, visit the homebound, provide counseling, build programs to help all kinds of people and in some cases raise a family and be a good husband of wife. But the church is not in charge of salvation selection. The church can't save you and neither can the church take your salvation away. "And they, continuing daily with one accord in the temple, and breaking bread from house to house, did eat their meat with gladness and singleness of heart, Praising God, and having favour with all the people. And the Lord added to the church daily such as should be saved. Acts 2:46-47
Part of the problem with silly beliefs like a priest telling someone that they will lose their salvation if that person leaves the church, is based on fear that the church will lose its hold on you and thus lose its financing. Neither are good reasons to sell someone a bill of goods that is not scripturally sound. God will provide for the church through His people. People of faith are always giving and self-sacrificing for the benefit of the church and for the betterment of mankind. They need not be proded to do what is already on their heart to do. The fear is from the preists and pastors that trust the system more than they trust God and God's children. "But woe unto you, scribes and Pharisees, hypocrites! for ye shut up the kingdom of heaven against men: for ye neither go in yourselves, neither suffer ye them that are entering to go in. Matthew 23:13
You will not lose your salvation for leaving the church. However, on behalf of those in ministry who are ministering to you and teaching the Word of God and working to benefit you and your family, I would be reluctant to just leave. Talk to your priest and leave on good terms if you must leave.
7 hours ago