They say that it takes the brain three days to adapt to change. Three days for the world to turn right side up again.
However in Seeley Booth's case, this wasn't true. Almost four years to the day he had been living without the love of his life. It was the biggest change he had ever undergone. Four years, and he still hadn't fully adapted. He still missed her smile. Her adorable laugh when she finally grasped why a joke was funny. The way she explained why she thought the joke was funny, even though that wasn't the reason. The way her eyes lit up everytime she caught glimpse of him. The adoration he felt radiating from her when they hugged. He just missed her. He missed his love. He missed Bones.
There are times when you lose a loved one, and over time you are able to move on and find another person to make you feel loved, and wanted, and special, and needed. However in other cases, rarer cases, the people that were together were destined for each other. These people are not able to move on. They simply have to learn to live without half of themselves.
The latter was the case with Seeley and Temperance. These two people were the most opposite people that you could find, however, together they just clicked. They got each other. They understood each other. They were able to use their strengths to cover up each others weaknesses, and they used that to become one of the strongest couples the crime fighting world had ever seen.
Although opposites, Booth and Bones were meant to be. Except now they weren't.
Booth was doing his best. He was lost without his love. Christine was his whole life now. He only lived for her, to prove he was sorry for what he had done to her. He'd never forgive himself for shutting down and abandoning her. He'd never forgive himself for losing the love and respect of Bones either. He was determined to prove himself again. To prove that he could clean himself up. To prove that he was able to take care of Christine.
Angela started visiting again. Booth was very happy about this as she spent some girl time with Christine. Although it wasn't the same as having her real mum, it was pretty close. Sometimes when Angela was visiting, Booth felt happy again. Christine loved having a mother figure around, and Booth knew that he had to try and find someone to become a more permanent role model for his daughter. He had to find another 'mate', as Brennan would say.
He dated several women, but none measured up to Bones. She was the standard that he compared every woman to. Or it was until Angela pointed out that no one would be able to measure up to Bones.
That was when he met Sophia. She was a smart, auburn haired, brown eyed biologist. She was very beautiful, and very smart. This was the woman that Booth would choose. He loved her, but not as much as he loved Bones.
And although he felt disappointed in himself, one day Booth had to move on. Even though he would never ever find and love anyone like he did Bones, he had to. He had to move on because Bones wouldn't want him to be unhappy. She loved him too much for that. And he loved her too much to let down his partner. His lover. His friend.