rules in love?

I keep on pondering on what may be the rules when it comes to love. Why is it that every relationship that I am engaging in doesn't last? 

From my experience, at first, relationships are like heaven. It is almost perfect that it can't seem to falter. But why as times go by it turns out like hell? The seem perfect becomes grotesque.

When she doesn't send a message or call me within a day or two, does it mean I am not important to her? When she doesn't say 'I love you' in any ways does that mean she isn't sweet? When she doesn't want to go to where I want to go does that mean she is inconsiderate? When she refuses to hold my hands in public places does that mean she doesn't really care?

I must confess that I am a little bit of a nagger. But is it a bother to send even just a single message a day? Is it too demanding of me to spare just a minute to say, 'Hey, I am just here.'? These are just simple, and if these are being neglected then there's no point to continue the relationship. 

Are these considered as my rules in relationship? If yes, are they so stiff?

Do you have rules in relationship?