As is written in the Scripture it is not ideal for a Christian to marry an unbeliever. However, if the couple is already married and one of them becomes a Christian, the Bible states they should stay married and not separate.
"To the rest I say (I, not the Lord) that if any brother has a wife who is an unbeliever, and she consents to live with him, he should not divorce her. If any woman has a husband who is an unbeliever, and he consents to live with her, she should not divorce him. For the unbelieving husband is made holy because of his wife, and the unbelieving wife is made holy because of her husband. . ." (1 Corinthians 7:12-14).
It is entirely possible for the believing spouse to share the gospel with their unbelieving partner and eventually lead them to Christ. But the odds of that happening is pretty slim. . . and the chance of that unbelieving spouse remaining stubborn for the rest of their married life is always 50/50. That's a big gamble. The thing is, marriage is already challenging without the need for the couple to have conflicting core values divide them. Why make things even more difficult for oneself by choosing a life partner who cannot, will not, participate in the fundamental worship of God that a true Christian desires?
Of course, everyone's journey to being closer to God may be different and I'm not in a position to judge. If you have already fallen in love with an unbeliever and you cannot imagine being without them, seek God's wisdom and grace. In choosing to marry an unbeliever you may experience specific challenges that you might not ever encounter if you were to marry a Christian instead.