9th Doctor:
He never thought you would pick him over your brother but you just waved it off with the accuse that you didn't trust him without someone who knew how to fly a time machine. Even though you didn't knew how to fly a TARDIS. The Doctor couldn't object of course, knowing you wouldn't leave even if he tried. And well he liked having you in the TARDIS with him and Rose.

10th Doctor:
After you had solved the mystery with the angels and found the TARDIS again the Doctor just couldn't leave you here to age like Billy. Martha didn't had anything to object ether, she took a liking of you too. You were overjoyed when the Doctor asked you to join him. Of course you said yes. He was very happy you decided to stay, he rather liked having you at his side.

11th Doctor:
After they had stopped the drill the Doctor took everyone to the TARDIS. You went to join Malohkeh but he knew it hurts when you went into cryo sleep so he said you should stick with the Doctor. You knew you had to so you went with the Doctor. You asked him if he could drop you off on the surface but he asked you to stay with him and Amy. You hesitated but knew you could trust him so you said yes.

Rory:
When the Doctor thought it was too dangerous for the Ponds he got them a house. Rory knew that he couldn't live in is house without you so he asked you if you wanted to stay with him. You took no time to grab your bag from the TARDIS and saying yes. Not before you threatened the Doctor about visiting you often. You knew he would or he would feel the wrath of the Nobles.

Mickey:

You stared at him as he told the Doctor he wanted to stay in the parallel world. He was going to give up his life to stay here? Why?? He had already told you a couple of minutes before but why?? You walked closer to him as the Doctor waved at him before he and Rose disappeared into the blue phone box. Mickey turned to you and wound his arm around your waved. As though sensing your thoughts he said. "Because you are all I need" You smiled and hugged him glad that he stayed.