If a husband consistently eavesdrops on his wife's phone calls with her family without her permission or knowledge and without any specific reason, is there a _shar`i) consequence for this? What about in the akhirah (afterlife) or on the Day of Judgment?
If we track back the Quran we are going to find that Allah doesn't detailed some queries because he puts some another auto-answering "if can i say" system in the human soul, it is clearly here that am talking about Al-Fitraa, if a Muslim wife complained about eavesdropping from his husband and the same case touches a non Muslim wife is it going to differ ? i don't think so, because this kind of problems are humanized, it means the Muslim or the non Muslim will going to feel that they have been cheated, it is the same feelings that causes same reactions in the same time with all human beings repeatedly, it is not like the standard believing judgments where a non Muslim will not care if it is Hallal or Haram, because they don't believe in what you believe in, so, Allah equipped you with Al-Fitraa that's going to judge without any arguing about Islamic rulings and what wounds Al-Fitraa will not satisfies Allah of course, i advise you to interpret on what makes your husband doubts about you and i suggest to communicate and solve the problem together.
Please read tafsir of following verse:
O you who have believed, avoid much [negative] assumption. Indeed, some assumption is sin. And do not spy or backbite each other. Would one of you like to eat the flesh of his brother when dead? You would detest it. And fear Allah; indeed, Allah is Accepting of repentance and Merciful. - Al-Ĥujurāt 49:12
In addition to that;
Narrated Abu Huraira:
Allah's Apostle said, "Beware of suspicion, for suspicion is the worst of false tales. and do not look for the others' faults, and do not do spying on one another, and do not practice Najsh, and do not be jealous of one another and do not hate one another, and do not desert (stop talking to) one another. And O, Allah's worshipers! Be brothers!" - Sahih Bukhari Volume 8 Book 73 Hadith 92
So it's prohibited, have faith in Allah (SWT) and He knows everything that we do;
Allah (SWT) says about wrong-doers
And the record [of deeds] will be placed [open], and you will see the criminals fearful of that within it, and they will say, "Oh, woe to us! What is this book that leaves nothing small or great except that it has enumerated it?" And they will find what they did present [before them]. And your Lord does injustice to no one. Al-Kahf 18:49
So have faith in Allah (SWT) and rely on him completely. He is best disposer of affairs.
Hope this helps,