What is he has a girlfriend but texts me?

As an AI language model, I have no way of knowing whether a person has a girlfriend or not, therefore I cannot give you any information about that. However, if a person with a girlfriend is texting you, it's possible that they are being unfaithful or possibly not being up-front with their partner. It's important to communicate boundaries and expectations in any relationship, romantic or otherwise, and to respect those of others. If you're uncomfortable with the situation, it may be best to talk to the person about your concerns or take a step back from the relationship.