When I was first getting to know my girlfriend, she told me about her relationship with her ex. She said that they were the best of friends, so it only made sense that developing that friendship into a romantic relationship would enhance what they had and bring them even closer.
After several years of emotional abuse and a bitter divorce, she left that relationship a shell of her former self.
Emotionally abusive people know exactly how to be a good friend. They show up when you need them. They say all the right things. They appear to be genuinely kind and generous to you and the rest of the world.