Heather was never the very affectionate type of person. And she never expected to ever "fall" in love either. She hoped to marry into a wealthy, and powerful family at, hopefully, a young enough age. And if she was lucky, someone who didn't want children either. But her views on those kinds of matters were changed when Alejandro appeared.
It had only been a few weeks of dating, but Alejandro insisted that they should very well tell everyone that they were an official couple. Much to Heather's dismay and unwillingness to admit that to anyone. No matter how much it would be wonderful (and a relief) to say that Alejandro was hers so everyone better back off. She didn't want to be viewed as someone who was "in love" even though she was.
Alejandro however, had no shame in showing everyone that they were dating. Of course Alejandro would be like that. He took pride in what he had and this is what irritated Heather on a daily basis. Random bouquet of flowers sent to her from him at work, always trying to play the guitar for her, and making her feel sick (a good kind of sick, mind you) in the stomach.
Heather hated (but did love, at times) all the attention he would give to her. But the worst part about it was that Alejandro knew that he was irritating her. He wasn't blind enough not to see her twitching in annoyance or to hear her small screams of frustrations. He loved getting her all worked up because he found her incredibly beautiful this way. But even if her anger was beautiful, Alejandro found that he loved every part of Heather.
Heather would never, under any circumstance, (or at least in her right mind) admit she's in love. No matter how much she truly was in love, she wouldn't admit it. It seemed silly to her and somewhat embarrassing when you admit how much you love someone. Especially when the person you love, just so happens to be your worst enemy.