Chloe,
I know this isn't what you want to hear, but living a lie like this is going to emotionally drain you! This is a HUGE thing in my opinion.
How long do you think you can keep it up for? I'm sorry, it's your life and your business, but I can't see this working, I believe it's wrong. If you love him and want the relationship to last, then I would seriously think of coming clean, or stopping escorting. A relationship is built on trust, I know you say that it's only sex and just a job, but we all know men don't see it that way. I believe they should have the choice whether to be with a girlfriend who escorts, or not.
Like I say this is my personal opinion, others probably disagree, but lies, distrust and decete only lead to heartache.
But, it's your life and your decision Hun. xx