Hi! I believe I can be of help with this issue.
First, let me say I can imagine how confusing and distressing this situation must be for you. Clearly you are an intelligent young woman and you have been watching yourself behave in ways that you know in your intellect are wrong, counterproductive, and revealing of a low sense of self worth. Yet you seem powerless to enforce your intellectual understanding on your behavior.
And this is actually the key to my answer to you that you need to consider and think about. That you are stunned at how you seem to still be behaving this way when it is and was so clearly negative makes you wonder if perhaps you were and are being abused and that's why you are seemingly powerless to stop and change your behavior.
And the answer is that this was not abused. Depending on your state laws, consensual sex with a 17 year old girl is usually not even statutory rape. The frustration you feel is not about him. He is clearly a user. He uses you and probably that other woman and probably his wife. And so his role in your situation is really peripheral. You are allowing him to use you.
What is of concern to me is you, not him. He is not a good human being. You are. But you have deep seated emotional and psychological problems. And THAT is why you find your intellect unable to stop your behavior. Because your behavior is not responding to reason, thought, or logic. It's responding to emotions and psychological confusion and distraught aspects.
Clearly, there was originally an attraction of his being an older man at first. There is also some unhealthy gratification you are getting from being used. There are other aspects that you need to bring to the open within yourself.
And this needs to be done in psychotherapy. This is very important for you. Yes, of course you need to stop immediately. And if it means leaving the job, so be it. You are a very young woman and I'm more worried about your long term health and wellbeing. So why can't you start therapy and sleep with him all at the same time?
Because it is like trying to understand and change the need to binge eat while the person is breaking open a whole box of cookies and getting ready to eat the whole thing and binge. There is no way to get clarity and the ability to change the NEED that is unhealthy without first stopping the unhealthy behavior if at all possible. That's why I am recommending if you have to, call in tomorrow and say you quit and don't go back. If you need a letter of recommendation for him to get another job, ask for a great letter of recommendation and if he says no, tell him fine, you'll just tell his wife why he doesn't want to give you a letter and ask her to help change his mind. He'll get the message real quick and mail you a letter. Whatever he says, do not meet with him as he will try to keep you in his orbit to use. Okay?
You need to then find a psychotherapist who works in the psychodynamic orientation. This is so you can look at deeply and completely the roots of your behavior that you want to change. Here is the web address for Psychology Today's therapist directory. You can sort by zip codes and when you see someone who seems like they might be helpful (you can see a photo of the therapist!) look at the listing and see if they list psychodynamic therapy in their orientations.
The idea here isn't that this of therapy are magic. It's that I want you to find a therapist who will form a strong therapeutic alliance with you and will help you look at the sources of both the low self worth you feel and the unhealthy need to be used AND the strength within yourself.
I wish you the very best!
Please remember to click the green accept button. Feel free to continue the discussion; my goal is to get you the best answers possible. Bonuses are always appreciated! If I can be of further help with any issue, just put "for Dr. Mark" in the front of your new question, and I'll be the one to answer it. All the best, XXXXX XXXXX