We consider physical level ex marital relationship as cheating?

But emotional and psychological level involvement with a person other than spouse or partner should also be considered as cheating. This does not happen in reality and many who have such relationship convince themselves that they are loyal and not cheating. But in reality spend lot of time with the person outside marriage , give gifts and always this person outside marriage occupies their mind fully. What are your views on this subject ? This is a major problem for most of the counselors.