One of the first things to do is to figure out the reason behind being attracted to a certain type of men.
Generally, if there is a past disappointment by a male figure (early in life) on a subconscious level, you may be trying to remedy the situation by reacting it (when drawn to that kind of men)
Examine (make a list, journal down, meditate upon this, etc) if there had been an important male figure such as a first boyfriend, father, teacher, guardian, etc. who in some way had rejected you in the past. It is a hypothesis only that your subconscious mind had made a mental map of the scenario and of the man and is trying to correct it in the present (with the new men you are attracted to)
A man who respects his girlfriend/wife/partner will not cheat. Respect is one of the keys to that. The other factors are fidelity, moral mind set of the individual, what he wants out of a relationship with you, etc.
Emotional Unavailability : Recognizing It, Understanding It, and Avoiding Its Trap by Bryn C. Collins (Paperback)