My sisters vs. my boyfriend

I have a sort of stupid delima i have been with my boyfriend for about 6 months now i want to know if i am right or wrong. Since i have been with my boyfriend we have spent so much time together a lot has changed in my life im in school working full time and have no transportation right now (car totaled in accident) and so im busting my butt trying to please everyone my sisters think other wise. They think that i am choosing my man over them. I sort of get where they are coming from we have spent much time together but a lot has changed in my life and one of my sisters is 17 the other goes back and forth from NY.  I want to know how i should go about it me and my boyfriend both work full time i dont see him only on weekends basically. Im taking opinions! Thanks ladies