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Seems to me that the BF thinks of LW as his property instead of his partner. Why are men so easily threatened by women's sexuality? The less experience a woman has, the less likely she is to know that her current lover sucks (in a bad way). Maybe that's why some are turned on by teenagers and virgins. It really is not loving... it's owning.
I agree with Cary that LW needs to dump this guy. It's easier said than done, but consider this a serious red flag for worse scenarios to come.