There is a lot of controversy around cheating and infidelity.
Some people, however, justify it by a list of reasons why their partners fail to fulfill their relationship expectations, and how they are driven to the arms of another person.

Most of these people make the reasons to be very legitimate; such as:
we lost the sparks in the relationship; she doesn't dress up sexy anymore; sex became way to casual, or just a lack of it; there is no more spontaneity; we argue too much; we are more friends now then lovers we used to be; we do not do sexy things, like dancing and romantic dates; there is no affection and excitement anymore; the relationship is ruined by the everyday stress from you carrier related issues; the relationship is to predictable and boring; the family is too much in to our business; one person is more dominating, therefore makes the other one more insecure and more likely to be capable to cheat!

However, the list can go on and on, and whatever the motive is, it is still doesn't justify the fact of deception. All of the above listed reasons are in fact typical relationship issues you may have with your current partner, or anyone new you meet.
I think we all need stimulation in our life, and we have a need to be constantly inspired; otherwise we start feeling trapped and impatient, and feel out of place.

So, men are often overtaken by the act of cheating, experiencing missing excitement in their life, indulging in to a new sexual encounter.
However, the men is not so eager to make any type of changes in his life, by getting involved in a new relationship and dating; that would mean giving up the old and adopting a new relationship 'rules'; getting used to another women; and ultimately being transformed to another women's men.
They are not ready to give up their 'comfort zone', despite all of the problems they may have in their current relationship.
So, an affair is an impulsive and temporary behavior, and it usually is not conclusive!

In spite of that, there are people who are determined to forgive the cheater, and make things work! It will require an utmost measure of human endurance.
The victim in this situation will be more reluctant to trust the partner again, even if she decided to let go.
I strongly believe, that after the act of infidelity in the relationship, where the trust is plundered; the future attempt to save it and make it work is ultimately doomed.

And, no matter how pleasing and agreeable he is, you will always have a concern on the back of your mind; and every time you try to make love, you will have a graphic vision, derived from the affair, of him with other women, the mistress. The victim here will become more vulnerable and sensitive, alert and insecure; anticipate the fidelity problems, which will accelerate the relationship to cease.

For some men the act of cheating is more physiological, then physical.
They may not necessarily look to fulfill their testosterone needs, but to satisfy their emotional dysfunction, to build their self confidence, to proof their manhood, and to boost their self worth.
Every time they commit the act of infidelity, these men block their romantic desires and genuine care for the person they are with, only allowing gratifying their need!

So, either cheating is physical or emotional, it is not justified!
You can not prevent or stop cheater from continuing to commit the adultery!
Sooner or later, he will continue to cheat again, repeating the same pattern.
However, it takes two mature adults to decide how their relationship should be; and it is up to them to make it honest and faithful!

So, if the women in the situation where the men cheats and lies; the solution is to move on with your life, and try to learn from this mistake.
The trust is broken, and you will never be able to repair it!
Another issue will be to learn to trust someone else again! But, this will take time and patience, and it will eventually work out to the best! Just keep and open mind and have a positive attitude!