Here's what's running through my mind: Is the partner in some way baiting or encouraging the jealousy? Giving off signals and clues that the jealous person really does have something to worry about?

Here's why I ask. The only time I was really jealous was when I was married. My husband told me I was crazy, etc. However, from the perspective of several decades, I see that he has a dysfunctional behavior pattern, not just with me -- but with all his wives and live-ins, many in number. In fact, over 30 years, this guy hasn't had a relationship that lasted longer than 5 years.

The dysfunctional behavior is that he always has more than one woman in his life and the other woman/women is "just a friend" who "needs" him or with whom he is just spending time with bec. they share the same interests or for business or whatever. This other woman or women take up a pretty big chunk of his time.

In short, he always keeps another woman right in his current love interest's face. I suspect he learned this behavior of playing one woman against another bec. he was raised by his mother and grandmother, with no male in the house.

I hung around a lot with my ex-hub and his next wife. Wife #3's mother got mad at me, and told me to butt out of their marriage. I was young, couldn't see what she was talking about. I'd always had to put up with the "other woman" in our marriage, the "just friend" woman; this was just the way hub was I'd decided. Now, in middle age, I see exactly what that wife's mother meant, and how X keeps several women around him, proving to himself how desirable he is, ramping up each woman's interest, then telling love-interest she's "crazy" to be jealous. Manipulative.

Do you have any friends who know your relationship and your BF well? Perhaps you could do a reality check with them. If they see your BF as manipulative, they will be reluctant to admit it. Friends want to stay friends and often don't want to give honest opinions until the relationship bites the dust.