Not sure

So theres this guy who is one of my good friends and we hook up occasionally after doing a run to mcdonalds late at night. Hes someone I can go to just to talk about my problems and hes been a big help and supports me but sometimes we can go as long as 2 months without talking. Last month he came to see me and we were kissing in his back seat and asked me if I was interested in seeing him and that we both will not see anyone else and I agreed because I love this guy alot.. I send him texts and messages on snapchat but he never replies. Ive noticed he does talk to a lot of girls but I always brush it off and make it seem like he only has eyes for me. My question today is can a guy ask a girl to date him and him only even if hes talking to other girls?