How to deal with memories and fantasies?

I am quite embarassed, but since I made an account here, I figured I might as well just come out and say it. A thing that I find very annoying and could hamper my progress is memories of porn. Literally, there are times where some scenes that particularly turned me on keep popping in my mind. I feel it might have something to do with boredom, as I remembered having some while at work with no customers and nothing to do, or while sitting in the bus on my way home. Sometimes I resist, some other times not. And a few hours ago it happened to be one of the times I failed and relapsed again once returned home, unfortunately. I'm wondering, has anyone had the same issue? And how did you deal with this problem? Thanks for reading.

 

Thanks guys.