This article is from before the Resistance existed. We can now apply it to the resistance and dating outside it.
It could probably be applied to dating even those who go to the SSPX at all, even if they profess love of Bishop WIlliamson.


Can Trads date Novus Ordo people?
Father Peter Scott answers the question:

Question: Can I date a Novus Ordo Catholic?

Answer:Dating is a preparation for marriage, in such a way that a man who would regularly date the same woman without any prospect of marriage would be foolishly exposing himself to the occasion of sin.

Consequently this question is no different from the question as to whether a traditional Catholic man could consider marriage with a woman who does not presently share his traditional convictions, even if she will come to the traditional Mass for his benefit.

It is sad to say so, but the differences between the traditional practice of the Faith and the post-conciliar religion are in practice so great that a marriage between a traditional Catholic and a post-conciliar Catholic is really not any different that a mixed marriage. In fact, it is made worse, that is more complicated and confusing, from the fact that the non-traditional party will use Catholic bishops and post-conciliar Popes to justify his liberal positions on practically every moral issue, as well as assistance at Mass. It frequently happens that the traditional Catholic party feels that he convince his future spouse about the truth of Tradition. However, if this spontaneous seeking for the truth in the present crisis, inspired by grace, does not take place before marriage, so that the two actually share the same convictions, experience tells us that it is very unlikely to take place afterwards, when the pressures of married life make the non-traditional spouse very likely to opt for the easy, liberal, watered-down, post-conciliar religion and morality. Moreover, it would be very presumptuous to think that one`s own faith would not be endangered, as well as that of any children to be raised in such a confusing environment.

Consequently, the Church`s warnings concerning mixed marriages apply to those one who dates a person whom he knows does not share his traditional convictions: “Serious blame, not unattended sometimes with danger to their eternal salvation, attaches to those who rashly contract mixed marriages, against which the maternal love and foresight of the Church, for very weighty reasons, warns her children….If the Church sometimes, for reasons touching time, circuмstances, or persons, does not refuse to dispense in these strict precepts (saving always the law of God and with all possible precautions against the danger of perversion), yet even so it will be difficult for the Catholic party to avoid suffering some detriment from such a union. A frequent result of these marriages is that the children unhappily fall away from religion altogether, or at least rapidly lapse into a negligence and indifference regarding it which is not far removed from infidelity and impiety.” (Pius XI, On Christian Marriage, §84 & 85).

A traditional Catholic ought not, therefore, to consider dating a woman who does not share his convictions concerning the crisis in the Church, the errors of Vatican II and the danger to the Faith presented by the Novus Ordo Mass, for:
She will not accept the Society`s doctrinal positions, which are simply those of Catholic theology and tradition;
She will not be submissive in questions of religion, nor consequently in other questions either;
She will seek compromises so as to please her family or the world, and consequently she will not willingly accept moral decisions made by her traditional husband, especially after he has sought counsel from a traditional priest, such as the use of NFP or number of children, presence of the television in the home, computers, video games, etc.;
Any children will be raised in an atmosphere of confusion as to the crisis in the Church, and will consequently have confidence in no priest, nor in the Church;
Marriage must have as its ultimate goal the sanctification of both parties, since they have to sanctify one another. They can only do this if they pull together, and have the greatest respect and appreciation for everything about one another, as well as the sacrament that gives the graces. For as long as she is drawn to compromise, this is not possible.
She would not even qualify to be married by a Society priest, since she does not understand the major impediment to marriage in the Novus Ordowhich is the reason that justifies the extraordinary form of marriage (Canon 1098 in the 1917 Code and Canon 1116 in the 1983 Code). Traditional priests would have to refuse to marry her, and so you would be forced to go to a diocesan approved priest, which is to found one`s marriage on the sand of a compromise.

This is not a question of good intentions, nor of the affection that such a person might have for a future spouse, nor of her willingness to sacrifice many things for the marriage. All this make a woman naturally attractive, and even to some extent supernaturally so. However, all of that is not enough for a successful Catholic marriage. There must be unity of Faith, of conviction, of religious practice, or moral decision, or conflict which mars the very symbolism and grace of marriage will greatly disturb it on both the natural and supernatural level. If such a situation were to occur, there is only one thing to do: stop dating on a regular basis, give her some time to herself, and let her think through her traditional convictions for herself. It has to be the understanding that if she does not personally share a future husband`s religious convictions for herself, then she will not be able to submit after marriage and the relationship is not going anywhere.

If one may marry only within “the resistance,” there’s the question of the many divisions and differences of opinion. Can a sedevacantist marry recognize and resist?  In a large number of instances, marriage candidates must be limited to those within one small chapel or who attend the Mass of a particular one or very small number of priests.
I don’t know the answer, but it certainly explains why there are so few resistance weddings. There are far more funerals than weddings and christenings.  There’s a chapel I’ve attended a few times where there are simply no people eligible for marriage. They’re either already married, and the majority are ages 50 and up. There are two large families with children too young for marriage, but even that has no potential as they are cousins. 

I was actually quite shocked to see people seriously believing they or their adult children should only date people who attend exactly the same type of chapel. As long as both partners are baptised Catholics and both practice their faith and believe the traditional church teachings on the important issues like contraception, abortion, education of children then all else can be worked out. Depending on the compatibility of personalities.

I even know Catholics who have married Protestants and the other partner has later converted. Though personally I think this is a risk.

If we have half the number of young men in the resistance actually believing that the resistance is the remnant

https://www.cathinfo.com/baptism-of-desire-and-feeneyism/