If we manifest everything then why does this happen?

If we’re constantly manifesting everything in our lives without even realizing it, how can you explain situations where a woman truly believes her partner is loyal and doesn’t even suspect that he’s cheating - and then later finds out he has another girlfriend or even a whole family? You could say that some of these women have a bad self-concept and I agree with that. But in some cases, these women actually have a good self-concept and it still happens. So how is this possible if they genuinely believed their partner was loyal and felt confident in themselves, yet their partner still cheated?