BEN GÖNLUMU COKTAN NIKAHLAMISIM DA HABERIM YOKMUS..!

what I understood there is no news about the wedding 

My Try:

I have given my heart to marriage a long time ago, I just wasn´t aware of it.

As ´gönlü nikahlamak´ is a saying, instead of lexical meaning , it is better to say ´ reserved´

gönlü nikahlamak -to give heart to someone , heart is reserved for someone.

My heart has been already reserved [for someone else] but I wasn´t aware of it.

Or ; simply ;

I have given my heart to someone else but I wasn´t aware of it.