One of the phases of love is mostly about understanding. It is at this phase that mostly people fail. Mostly people crib about lack of time to spend with their loved ones. It is very true that spending time with ur loved ones brings in a lot of happiness to one's mind. So I believe its the onus on people to devote enough time to their loved ones. Never should a man feel that the person whom he loves is devoting a lot of time elsewhere when the same could be spent with him. I think it is this kind of feeling that keeps growing in individuals and gives rise to various complexities.
I would take the an example of a child whose parents both go for work and love the child a lot. A situation like this could bother the child so much:
A child will ask his mom to take him to an amusement park on a weekend. Mom says she is really busy at work and will take him some other time. The child kind of compromises and then diverts his mind. A month later, his mom totally unaware about the weekend trip she had promised, goes off to a party. Now this will have a devastating effect on the child. The child will start thinking that a party is much more important for his mom than taking him to an amusement park. He will be able to justify that his mom will be busy with work always but will not be able to justify the party going act. Its simple "if my mom could go to a party today, she could have taken me to the park instead". Its this kind of feeling that leads into misunderstandings, fights, etc which will become highly unresolvable. Counselling will be needed etc etc etc. Y all this ? instead bieng a bit more understandable helps so much ...