There definitely are female characters who seem almost thrown into a movie last minute to give the male lead a romantic interest. I say movies because that's the medium where I think I started to notice it first. I feel bad for actresses who probably got into this line of work because they're passionate about acting, but then they're given roles that don't have much going for them. That being said, there are female characters out there who are simultaneously in a romantic plot and have other interests driving them. You should start a rec thread in the GC, OP.