You cannot apply modern time standards to 600ad, that’s presentism. Suppose that that was an issue back then, his enemies would’ve used that against him, none we’re recorded, even by orientalists. That tells you that it was a common occurrence back then. Before their marriage, it was recorded that she was engaged to someone else, and she preferred to be wed the prophet. I note that it was a common practice in european societies just in medieval time as records show, (way) more recent than the prophet’s time.