What does it mean when a guy acts like he is interested but still flirts with other girls and what do you do?

Most independent women wouldn't allow a guy to flirt with other girls. If he's steady dating you then he's no longer a free male to flirt or date others (this applies to young women as well.) Tell him to knock it off and if he doesn't then ditch him! he's not interested in you, ALONE. some guys can't live with just one girl. i tell you, BOYS ARE ALL THE SAME. better date someone who had lots of ex-girlfriend, believe me! its hard to explain.. but my aunt told me once. (he's husband had a lot of ex-girlfriend before in their teenage years and now he's very loyal to her) so STOP wasting time on that guy! he'll do no good to you. :)