Most people have a sexual past...do you think this way with women in general (ie picture other 'dudes' inside her) or is her sexual past only an issue because of her job as an escort? I personally don't see why you should view it differently to a girl who has multiple partners that hasn't escorted. It's in her past and she's been very open with you. If you care for her and want to make it work you need to put her past job where it should be - in the past, and move forwards. It's not very nice for her if you are thinking about her with other men when you are having sex with her, because I can guarentee she won't be thinking about her past clients when she's having sex with you - she will be thinking about you.