who did start a dishonest?

It depends. When someone started to edit the things they say to their partner or started to hide something from their partner then his or she is the one who became dishonest first. The key to successful marriage is trust, love and communication. If you really loved someone and realized that at some point in your relationship he or she became dishonest then you should forgive him or her and give them another chance. But if they still broke your trust then it is time to let go or have a heart to heart talk.