There are two questions but related.
1. How do we know whether the marriage/husband/wife is a magic victim?
2. How do we know who did magic on us? Are there any sharia ways to know?
May Allah reward you with good.
Shaykh Adel As-Sayed:
People usually hasten in deciding that a situation like this is due to magic. It could be a psychiatric reason, it might not be magic so not everything is to be attributed to magic. Magic isn’t that common for us to suspect it in every situation. This is the first point.
The other point is, magic has to be fought, i.e overcome and revealed, only by taking refuge in Allah; by Tawhid, by fixing our Tawhid, by strengthening our iman and then by this strong Tawhid and iman we make ruqyah with Ayatul-Kursiyy, Surah Al-Faatihah, al-Muwadhatayn, this is how we need to fight magic or anything related to jinns. We don’t go to people, mashaykh or anyone to read on us, we do not ask anyone to read on us, this is not right. Those who were known to make ruqyah to others were Ahmad bin Hanbal, Ibn taymiyyah, but not anyone are these great imams, they don’t possess this great iman like these imams.
So you perform ruqyah for yourself, don’t seek it from anyone. Fix your Aqeedah, fix your Tawhid, fix your trust and certainty in Allah and ask Allah to reveal it to you with dua. There are authentic duas proved by the Prophet, peace be upon him, for this.
This is the only way out – Aqeedah, get rid of any disobedience, make ruqyah with Quran and make dua to Allah to break any magic and get rid of any magic, there is no other way except this.