ANSWER:

If he accuses her of having an affair with another man, this is slandering and is punishable in Islam by flogging 80 lashes unless he provides four male muslim witnesses, a confession or he would take an oath by Allah 4 times that she committed adultery and the fifth oath that may Allah’s curse be upon him if he was lying. 

What is the sharia law prescribed for a husband’s extreme suspecting and doubting behavior towards his wife? To an extent he calls his wife a characterless and use abuse hurtful words towards her and falsely doubts her having affair with her brothers and uncles.