Deal breakers are just the things in life we aren’t willing to compromise on within a relationship. I think it’s good to have standards and expectations for who ever you date/marry and to not settle
If I may press this issue, which “pressing” may make sense to some and not to others:
A true marriage is not “a deal”, and not “a relationship” either - it is a fully human reality, a covenant having a spiritual significance that reaches into eternity. A human marriage is “until death do you part”, and at the same time reaches beyond death in what it reflects and bears witness to: the eternal covenantal union of Christ and HIs Church. (Eph. 5:21-33)
For this reason, it is very, very important to hear and follow God’s direction - His will - concerning a possible marriage. A true marriage has three involved, not merely the man and the woman: God is present in a true marriage; His assent to the marriage is essential to the truth or falsity of it. When God says, “This is your wife” to the man, and “This is your husband” to the woman, THEN with absolute confidence you can know this marriage is and will be the beautiful fulfillment of God’s will.
This does not mean the marriage will be without trials and difficulties. It does mean that all of those trials and difficulties will be blessings, chastisements ordered to the sanctification of the spouses.
This also does not mean that God cannot work for the sanctification of the spouses in other marriages! Such work, however, will be more difficult, more costly and more painful for the spouses.