Sure is, Mrs. Matthew. The next step on your road to awakening will come when you see that the "grave reasons" and "serious motives" also fall apart on closer inspection.
At SSPX if you brought them this article they'd tell you that NFP is not wrong in itself but only being misused. They'd blame it on Novus Ordo couples-counselling and say that these families have strayed from the path of Pius XII -- whatever that is. I'm not sure anyone has yet explained what a "social" reason not to have children is. That was probably a Freudian slip since what Pius XII was teaching was really socialISM.
But if there are no grave reasons to use condoms and so on, there are no grave reasons for this either.
I will be praying you and your family remove yourselves from SSPX before the flood hits. Matthew's won my respect for letting me post here, and believe me, I genuinely am frightened for you guys. I could also be a devil trying to lure you away from the sacraments, which is why I ask only that you KEEP RESEARCHING. God will show you the way if you genuinely want the truth.