Clark and Chloe are friends. And Clark acts behind Chloe's back.
Clark: I'm sorry. My obsession
pushed me past the line with you, (made him go beyond their friendship?)Chloe.
Hi Madhulk,

I am not sure if I have understood this correctly but it should mean that Clark regrets that he did something beyond the acceptable boundary; something unacceptable in a friendship.

Thanks, Peaceblinkfriend!