Did he lie to me about not cheatin (10 points to the best answer)?

well da otha day me and my guy were layin down (after making out) and i used his fone. I noticed dat he had messages in his phone from another girl. He wastextin her sayin things like "are you still lookin fine" and "i had a dream dat we met up and had n the gr"I startes cryin and he said he dreams about her months b4 we started goin out adn they use to mess around. Then he held and kissed me 4 20 min and told me to stop cryin . And b4 he left 44 work he hugged me at the dorr for 10 mins. He said he did dat becuz he dont wanna see me cry and diddnt want to leave me feelin dat way. It jus seems a lil shady and dat he is try to get back on my good side to keep me round. And o yea he promised dat he wud neva text her back again. But still how am i suppose to kno if he does not messages can be deleated. What should i do? Is he lyin to me ?