How to turn absolute Hate into Love?

In the first book MMC and FMC have a child and are in love so deep that each would sacrifice their lives - and in one case their immortality - just to make the other happy.

But in the prequel - what I'm writing now - it turns out that they are genetically programmed to be complete opposites, and to hate each other so much that they want to tear off their limbs and kill each other in the most gruesome of ways. So how do they learn to stand each other, then like each other, then love?
It can develop over a year or two, but it has to happen.

But right now, I can't think of any way for them to be drawn to each other, or to even consider the other as a human being.

Any suggestions on how to bring them together will be very appreciated!

Maybe I can help seeing as how my romance started with a rival prince and princess and ended with a happy king and queen.

First things first I made her keep her identity a secret for if he knew she was the princess of the country they were waring with, he would have had her head on a pike at his castles gates. She actually braved his lands and poisoned him and his men, capturing him and taking him as her hostage. It angered him to no end but he was amazed at her courage and knowledge.

Along the journey back they run into a lot of obstacles and I think the first turning point for them was when she found a poster of her young sister being hung for something that was actually her fault. She was so upset that he gave her a full 24 hours of grievance time and relinquished his weapon to her. After that they had some rocky moments, specially when he found out she was the princess and married her against her will for her lands. But just simple things like losing someone, over coming a fear, learning a new skill, seeing them in a new light every now and then.

There truly is a thin line between love and hate. My MMC couldn't stand my MFC's touch but when he was injured and needed healing he had to submit and learned she wasn't all that bad.

Hate grew to acceptance, acceptance to respect, respect to like, like to need and need to love.

Hope I helped somewhat, in most rocky journeys when the male and female have to depend on one another, love happens.

Make something happen that makes the one respect the other, which makes them treat each other civilly. Or make something happen that makes them realize they were basing things on a misunderstanding, and that they had the wrong impression this whole time.

Maybe you want to watch that old movie You Got Mail, with Meg Ryan and Tom Hanks. Or When Harry Met Sally, also with Meg Ryan (and Billy Crystal). Those relationships were both based on intense dislike fopr each other that later became love.

I would put them in a situation that forces them to work together. If they are programmed to be genetically opposite, then they will have opposite talents, fields of interests, etc... Put them in a scenario that forces them to both use their unique skills to succeed. It also makes it so that one cannot survive without the other. :)

I know that this might not help that much--especially compared to other people's STORY ideas--but I have an experience that relates to my real life.

My boyfriend and I had a rocky relationship. When I was a freshman in high school, he was seen as the "bad boy, most AMAZING guy ever" and I just didn't like that. Then my best friend started to fall head over heels for him and that only made me dislike him more. Then, my sophomore year, he ended up sitting right next to me in Chemistry class. He tried to talk to me but since I pretty much loathed the guy, I hardly ever responded.

This whole situation ended up in both of us having mutual hatred for each other. Until my abusive exboyfriend started to make me cry. He saw me crying and asked what was wrong/gave me advice. We started talking and through his help, I got away from my exboyfriend.

Somewhere along the line--whether it was him holding me when I was upset, or both of us bonding over the fact that I can't do Chemistry to save my life--we managed to fall for each other. And now we are dating and couldn't be happier.

It was through my preconceived notions that I ended up hating him in the first place. Then, once I started to get to know him, I realized that his intentions weren't bad at all and I ended up falling for him.

I'm not sure if that helped, but I hope it could have sparked some sort of creativity or something!! :)