If slaves not allowed to marry how fro-americans survived till now ?

As I understand the situation there were quite a lot of young women captured as well and some slave owners were interested in breeding more slaves so did allow slaves to cohabit. Slaves formed families but at first slave owners would not allow them to get married in case they wished to sell one of them. That was a legal marriage but no doubt as the slave adopted christianity they would at least have church service but even then they were liable to be split up. .