When a girl get married, her parent especially her mom always try to give her daughter good advice which may need her in her new family (or I can say her husband's family, including husband's mom, dad, bro, sis etc). Many mother says to her daughter that "never tell every problem to your husband, that my cause problem in the family". That's true, it may coz problem to the husband's family but if you don't tell, it will coz problem to you only.
When your husband goes to office, other family member may look at you differently. In many ways they might create problem to your life. In most cases it effects mentally. When your husband comes back to home they start saying bad things about you to him. Before he sees your face, his ear is full of your bad impression. This might cause problem to your personal relation too. May be he will start lossing attraction to you. Because you didn't tell him what actually happen to keep peace to your husband's family. From your end he didn't hear
anything, so he believed to their family member as they make you the culprit.
My advice to you will be keep explaining everything to him, if possible show him some prove. Then let him decide. May be he won't believe you every time, but this will help you to reduce wrong impression always.