The hard part is walking the fine line where each party's needs are being met (mentally, physically and emotionally) and everyone still has enough space and free time.
Part of what attracted me to my last partner was that she had her own schedule and agendas. When she had time she'd drop by, it was nice to have someone there fairly frequently but not all the time. As they say, abscence makes the heart grow fonder. People need time apart from each other (or at least I do) so that we don't drive each other crazy.