Erik was glad that Christine decided against going to the masquerade. He didn't want to tell her, but he didn't wish to see Raoul. He was afraid that if Christine saw her former lover, she would regret leaving him. "That's stupid. I need to stop thinking about that," he thought.

Christine could sense that something was wrong. "What's the matter, Angel?" She asked.

"I was just thinking," Erik said nonchalantly. He was apprehensive about telling Christine what exactly he was thinking about.

"What were you thinking?" Christine inquired.

"Okay, I know it's incredibly stupid, but I am glad you turned down the masquerade. I was afraid that maybe if you saw Raoul, you would regret leaving him and instead going with me," Erik confessed.

"Darling, we have been married for two months now. Not for a moment have I regretted running away and marrying you, nor have I wished that I chose Raoul. I love you, Erik," Christine assured.

"I'm relieved to hear you say those words. I love you too, Christine!"

Erik was extremely happy to hear his wife's reassuring words.
You see, Erik was not used to being loved. His mother sold him to traveling gypsies when he was a little boy. The gypsies treated Erik like he was an animal. He was kept in a cage and beaten for the entertainment of large crowds. He was even called the Devil's Child. Erik endured many years of harsh treatment. He was physically and emotionally scarred from his time with the gypsies.
Of course, Christine knew about all of this. She did her best to show her husband how much she loved and appreciated him.
Despite her support, Christine knew that she could not permanently chase away Erik's doubts and fears. Like it or not, Erik's worries were a part of who he was.
Erik knew that his wife loved him. He tried his hardest to reassure himself of her love every day.
Both knew that all Erik needed was time. Time and love.