Larry and Megan are the best example of this--they develop a relationship which entails X number of dates, X number of sleepovers, X number of wild cards. Megan holds the wild cards yet she is completely okay with the schedule. She quite an independent person herself. And the relationship doesn't suffer. She looks out for Larry, offering her apartment when he gets kicked out of the steam tunnels. He looks out for her, making sure she has a telescope when he goes into space and sending her notes in calligraphy. The end of the series implies that Larry has gone to join Megan.
Alan does worry about his sons not being able to commit to and manage relationships, much less a house--especially since Larry is Charlie's role model. Yet even Alan must admit that his wife had her own interests and needed her own space.
I was a fan of the Don-Robin relationship since both are such entirely career-driven people. Charlie and Amita are less so--at least, their careers allow them to stay within each other's orbits--yet they both have separate interests and strengths as academics. The brothers end up with women who are tough, not because they are belligerent but because they are their own people.
