I would gather a bit more info 1st before you jump in at the deep end....like everyone else has said, a lot of people use the term darling/babe etc, personally I wouldnt like it, and I dont think my fella wuold either if another man was texting me things like that.....but everyone is different......also if he is having an affair and wants to hide it, he could easily use that excuse of.....lots of people call eachother darling and theres nothing more in it!!! Bide your time and keep checking the phone, maybe text the number yourself saying something like...I miss you x and see what reply you get back....if I really thought he was up to no good, I would do it regardless of who I was texting, and wouldnt be bothered about the consequences, but thats only if your feeling really brave! As I said before, bide your time and try and get more evidence if theres any??? and also ask yourself if he has been going out a lot at night etc, without you, is he secretive with his mobile? If so, I would check it when he has gone to sleep.....you dont have enough evidence at the moment, and if he is doing you wrong, he could worm his way out of it easily....keep checking it and get some real proof before you jump in at the deep end..best of luck!