WHY IS MY EX STILL TEXTING ME

Like fuck!! He broke up with me! Im ready to move on and have accepted a future without him. He keeps reaching out. Hasnt gone a day without texting me or sending me a funny post on instagram. I never reach out its aways him. Or sometimes we chat on the phone. But idk. We do get along great as friends and we rarely argued. He broke up with me to “focus on his career”. Whatever i know thats half bs. But like ugh fuck. As soon as im doing good his name pops up on my phone! Im not the type to block people for no reason. Hes not rude or just wanting sex, he actually likes to talk to me about stuff in his life and ask me how im doing. It wouldnt feel right to block him because technically were on good terms but idk what to do. Just keep texting casually? I definitely am guarded again and have a wall up. I keep things friendly and simple. Im not desperate for sex, even though he said he wants to again. (Hes not hooking up with anyone else and neither am i)