My ex and I used to be like this. Acting like best friends where we'd pick at each other and have fun as well as being a couple. I attribute that to the reason she waited 7 years to cheat on me then blame me for the relationship ending

It is and it isn't. Having a relationship is not like having a best friend. I do not imagine kissing my best friend. It's a deeper bond, and it's not all about intercourse. It's about respect, communication, you are friends but the love you feel is different from the love you feel for your parents or friends. You feel this sense of peace and safety when you are in a healthy relationship. Your partner is someone you think about first when something happens to you (good or bad), it's someone whom you get nervous over, or more like excited. Sometimes you compromise for their sake. Yes, they are your friend as well but it's much more than that. Love is a lot more than that. 

It's hard to explain but relationships are not like in the movies. You do work to maintain it healthy and nice and passionate but not to the point where you lose yourself. But nowadays relationships are kind of fickle so it all depends on the people. But love is...is hard to explain in words.