I've cheated and I've been on the recieving end as well.
First it makes a HUGE difference in changing yourself (as a cheater) to admit publicly what you have done and make friends who can help you to hold you accountable to being fully honest and open about what you think, what you feel, what you want, what you need.
Most often, lying/cheating (in my experience) follows lying to ones ownself about needs and wants. If you get used to lying to yourself, lying to others follows.
On the recieving end, it's most helpful to me to understand that other people lie and cheat because something is wrong. Whether they are too afraid to be open about their desires (which may or may not be based on MY reactions to them in the past), or too afraid that they will be told no, or too afraid to even look into themselves to find the real need that they aren't fulfilling in themselves or they are addicted to the "high" of doing something "wrong".
If I can understand what INITIATES the issue, then I can figure out if that issue is one that CAN BE solved within the dynamic of the relationship. Sometimes it can, sometimes it can't. If it can-then letting go of the anger and rebuilding trust follows naturally along the progression of resolving the issue that led to the lying and cheating to begin with.
If it can't be solved within the dynamic of the relationship, then I can let go of the anger and begin to forgive-but not worry about rebuilding trust; because I know that the lying and cheating was a "karmic" (for lack of a better word) way of showing me where the underlying issues were that meant the relationship wasn't going to work anyway.