3 It is not his first infidelity
If you have heard of his previous sentimental experiences and his deceptions, there is a good chance that he will repeat the same pattern with you. Generally, an unfaithful person will not tell you about their unfaithfulness at the first opportunity. On the other hand, a behavior which does not deceive: it will never confess to you the reasons for these previous ruptures and curiously does not speak any more to any of its ex.
4 He lies very well
He has this amazing ability to lie all the time: to his boss, to his friends, and you even took him in the act of lying with you. Admittedly, these are little lies of nothing and for nonsense but the so natural way and the ease with which it lies is frightening. So that sometimes he believes his own lies and is unable to discern the true from the false.