Almost always, misunderstaniding makes simple probelms are hard to solve. and widen the gap inbetween...
if u just put the idea of cheating in your mind, you will change with him without you knows which could make the gap wider.
sometimes men want to be a little far (emotions and maybe place) from the lady they love, sure im not talking about new love, its just in their nature. and that doesnot mean that they dont love her anymore or they are cheating on her. being a little far, will make his after a while closer even than before.

if you are sure that he is seeing an new woman that doesnot mean he is cheating also... maybe he is helping her with a private problem that she dont wanna people know about....

but if you are sure about what you are talking about, all what i can say is to face it face to face... we are adult here and there is no need to search about it from behined. we must be responsible about our behaviors and words

take care dear

 I'd never spy on anybody. In my point of view the truth always comes out in the end, whatever it is.  If he's disrespectful in any way turn your back to him and go away.    

sum realities dont need proves so if u think he is cheating and u r still wid him then u r wasting ur feeling to a wrong man

TRUST IS EVERYTHING IN RELATIONSHIP
IF U DON'T TRUST HIM
THEN LEAVE HIM