What would you do if you were seeing a guy and he was openly seeing some1 elts?

ok so i have been seeing this older guy for 3weeks but i have known him for like 2 years and after the other night he told me that we needed to be really honest with each other so i said fine so then he went on to tell me that he was really intrested with this girl but they are not together or anything because she lives in a nother state and they both have agreed to date other people but he was acting like he really liked me and stuff so after telling me he said he was leaveing out of state to go see her but he said (babe im not going to have with her promise ) what should i do or think ohh and he told me he dont want to have with me cause he dont want us to get to attached to each other but i really do like him what would you do plz i need help ?