A relationship without trust is in trouble. Trust could be lost by an affair or any of a number of other reasons. This article will give you some ideas on how to rebuild trust in a relationship.
You have to understand that true trust is something that is developed over time, but lost in an instant. It therefore can take quite some period of time to rebuild trust. Do not despair or give up, just work diligently toward it.
If trust was broken by an affair, the marriage can survive and many do. The first thing to do in the case of an affair is, of course, to completely end the affair and all contact with the other person. If that means changing jobs or moving, do it.
As for specifically how to rebuild trust in a relationship:
1) The best definition of truth I have heard is when the word and the deed are one. Say what you will do and do it. Never say you did not do something if you did it. If you promise to be somewhere at a given time either be there or at least call to announce any delay.
2) Complete honesty is a must. Lies just are not going to work. The less you lie the less you have to remember! Tell the truth to your partner and that will encourage him or her to be truthful with you. This helps begin the trust rebuilding.
3) Do not try to keep secrets. In a brand new relationship there are things you would be wise not to share, but in a marriage or long term relationship that is just not the case. If the secret comes out from a source other than you the rebuilding of trust is jeopardized.
4) Show some faith in your partner and your relationship. This might require a little stretching on your part, but if you act suspicious of your partner you encourage them to be suspicious of you. That kind of relationship is no fun.
5) Understand that there will be bumps in the road, that is normal. Never make a mountain out of a mole hill, discuss concerns or problems and get everything out in the open. Be reasonable with your partner and not make unfair demands.
6) Always be courteous in your speech with your partner. Nagging about anything is a real drag on a relationship. If he or she promised to do something and did not, mention it and ask for it to be done, but do so firmly and politely with an expectation of fulfillment of the promise.
7) Expect yourself to do what is right. Give yourself credit where due and simply acknowledge weaknesses with a commitment to work on them.
Relationships require trust between the two parties. Do not expect miracles over night, but work toward trust on a daily basis.