As I've said before, I'm not making a case for monogamy here and hell, if you want to use the Bible to justify your actions, you could throw one of your 'concubines' out the door and let her be gang raped all night to save your own skin. The Bible records that and never says a word against the guy. In fact, when he chopped up her body and sent pieces of it to his countrymen, they were all outraged -- about the offense committed against him.
It's irrelevant because I believe people can have loving, satisfying non-monogamous relationships. You don't need to sell me on that point. From what I've heard, it takes a lot of trust, open communication, and a willingness of all parties to be involved in that kind of relationship. It's not my cup of tea, but to each her own.
My problem, as I've said before, is that you are putting your own pleasure over the well-being of another person. You don't want to be monogamous? Cool. Be with women that don't want a man to have an exclusive relationship with her. If it starts out that way and at some point, the woman changes her mind and wants an exclusive relationship, tell her you have no desire or intention to ever have that kind of relationship with her. That you intend to see any woman you want to for the indefinite future. If she can't seem to let go, but is clinging to you from insecurity, etc break it off, don't string her along with false hope just because you find her a tasty treat.