Such a nice post! Let me see how to parse my thoughts and write a comment:
1- Relationships have become SO complicated these days because of media control and others. Maybe it's just my opinion, but the best relationships are giving relationships, where both like to give each other. There is a lot of conditioning around us these days that have made people selfish and full of fears. As a result most people think of the partner as little more than an object, a sex machine, something to show off to my friends, someone who pays the bills, etc... It's pretty fucked up, but it doesn't change that fact, and modern reggaeton music doesn't help with these elements.
2- Some of the things you mention here are more for an international culture, kind of... I mean, in some cultures poligamy is normal and accepted, and in other people just use each other and try to force change (just like you mentioned). Good examples are the rich guys who hunt for pretty girls and she accepts him (because he's got money to give presents, he's got a car, etc...) and then he betrays her... you got what you deserved.

3- It's important to know your partner, just like you said, and it's important to accept the fact that people don't change EASILY, I don't understand why most people fail to understand that fact, honestly. Women have sex with delinquents, get pregnant and then expect things will magically change, that's delusional. Same with men, they want a 18 year old hot chick who wakes him every morning wearing nothing but an apron with a breakfast that does the chore of the house and also earns money at a big company, no one's THAT perfect.

Anyways, just some random thoughts about this messed up world and the relationships of people. Keep up the good posts!