Why does he keep texting me? Is he just trying to use me?

He wants his cake and eat it too , maybe he is bored with her at times so he runs to you . In other words , keep avoiding it , dont do it again , been there , done that and you will be the one who ends up getting hurt . because she is his main and you technically are his side-dish . Sorry im a little harsh with my words i was with a man he had a gf i thought it was working he took me out bought me gifts but guess who he is with , her and he refused to fix the issue so i left.