In the second stanza Coldplay starts to sing, "Tell me your secrets", which means he wants her to tell him his deepest thought and hoping to hear that she still loves him. Coldplay follows it with the lyrics "and ask me your questions", indicating that he want her to ask him questions about what has been going on and how he is doing so he can explain it. If she asks a question it means she still cares and also wants to save the relationship. What Coldplay means by "Oh, let's go back to the start", is that he wants to go back to the beginning and try this all over again. He hopes that by explaining what happened, it will clear things up.
The last two lines of the second stanza are very important. He keeps "running in circles", trying to figure out what to say to her. Going back and forth with the decision to talk to her or wait for her to talk. Instead of being a man he flips a coin to decide their fate. The "coin" is a metaphor for fate. Heads means that he will wait for her to talk to him, but he has not said anything, which explains the "silence apart". Tails means he has to talk and make things right, but fate has decided that is up to him. He has to fix the relationship, which is why the coin keeps "coming up tails".
After the second stanza comes the hook. In the hook Coldplay is saying that he regrets not telling her that he doesn't want the relationship to end and now he is hurting everyday. When the lyrics "nobody", comes it means he went looking for advice, but all he had to do was follow his heart. They always told him the same thing that it wouldn't be easy, but it's for the best and so he listened to them instead of himself. They also told him that he'd get over her, but he has not; he wants to "go back to the start" when everything was perfect with their relationship.
The first stanza of the second verse is about him trying to figure out how to make the relationship work, using logic and reasoning.
