What is the ruling regarding one who is about to get married while regretting having stopped praying previously?

Most scholars hold the view that one who abandons prayer is a disbeliever. They cite as evidence the Prophetic saying: "Indeed, between a man and disbelief or polytheism is the abandonment of prayer," and his saying: "The covenant between us and them is prayer; whoever abandons it has disbelieved." Consequently, it is not permissible for one who abandons prayer to marry a Muslim woman, based on the Almighty's saying: "And never will Allah grant the disbelievers a way over the believers," and His saying: "And do not marry polytheistic women until they believe." If the one who abandoned prayer repents and turns to Allah, Allah will accept his repentance, based on the Almighty's saying: "Say, 'O My servants who have transgressed against themselves [by sinning], do not despair of the mercy of Allah. Indeed, Allah forgives all sins. Indeed, it is He who is the Forgiving, the Merciful.'" At that point, he may marry. If the one who abandoned prayer makes up for the prayers he missed, that would clear his conscience; however, those who consider him a disbeliever do not obligate him to make them up.