What you’re facing here is not a question of respecting another person’s right to have his own religious beliefs. What you’re facing is whether you are willing to enter a marriage knowing that you will be “spiritually single.” You will not be able to share what you have said is an important part of your life with the person who will be the most important human being in your life.
You are also contemplating starting a family with someone who will, at best, not be a part of your children’s religious formation; or, at worst, undermine your ability to raise your children to be strong in their Catholic faith. He may not intentionally do so, but his lack of interest in the Church and his non-Catholic beliefs will play their own role in your children’s formation and can contribute to your children not developing a strong Catholic faith.
Marriage is not an official stamp on a romance. While it is important to marry someone you love, it is also important to understand what marriage is: It is a vocation intended to form a couple in sanctity and enable them to raise their children to be saints. For that reason it is important for someone contemplating marriage to find a partner who shares his or her religious beliefs and is willing to work with him or her toward heaven. That is why the Church discourages marriages outside the Catholic faith.
I cannot tell you whether you are with the wrong man. That is for you to decide. All I can tell you is that I strongly encourage you to carefully consider whether this man will be able to help you fulfill the purposes of marriage in the manner that the Church understands them.