I noticed some suspicious texts in my boyfriends phone could he be cheating?

One day i noticed that my boyfriend had texted some girl saying "i finally found you lol" and saved her number as chick from work she replied saying who is this? And he replied saying his name. Then he texted er again and she finally remembered him like two days later. First off he usually never saves girls numbers second off girls usually text him not viceversa. Then one day we got into his car and i said oh yougot a text from that chick from work and right away he grabbed hia phone before i could read it and when i asked him who she was i said oh really? Whos thia girl you workwith? And he jist saidbabe she's some big black girl i work with (not offensively he's just atrltracted to dominican girls). All of a sudden recently he reactivated his facebook aftermonths of not using it to find someones number but chooses to keep it up for some reason and he's OBSESSED with it!!! Then i go throughhis texts and notice he asked for this girls lastname to addher on fb and she replies and then texted him at 2 am asking if he's still up. I wasnt with him that day but i noticed that the previous texta werent there and he NEVERr erases his texts. Then i go on facebook to see her and i find out she's dominican and attractive just not what he'd go for usually but he still lied about who she was. Could he be starting to cheat on me? Sorry for the essay haha