She is the main reason

After dinner, Rachael accompanied Edward to play with the blocks while Andrew and Justin stepped out in the garden for a bit to discuss a few things. 

… 

[Garden] 

"How long are you staying this time?"

Justin did not answer, instead he kept gazing at the night sky.

After keeping quiet for a long time, he finally said, "It's not safe to raise a child in that atmosphere." 

Andrew understood what he meant and nodded. He couldn't agree more. "What are you planning to do?" 

He sighed and shook his head. "I don't know Andrew, I have never been so confused in my entire life. At first it was just me so I could do whatever I want but now with Edward around, I have to think at least a hundred times before doing anything." Having a child by his side had changed Justin's entire life.