[DF] Lecherousness (Dwarfs only) - at what cost?

[Rune]

I am playing a dwarf in a DF game, who was exiled from his home clan because he slept with the princess (and some other of the women). I had kind of figured that it would just be a part of his background story, but I see now that it is more than that: whenever he sees Dwarven female (at around his age) he starts hitting on her with the clear intent of bedding her.

So I need to make an appropriate disad. And this is where I need help. There are a number of factors counting in, and I will try to list them as I see them, in order to give a fair view of how serious it is:

1: He only hits on dwarfs (females). No cross race sex or homosexuality here.
2: In this world Dwarfs are not common among humans (which is where the party usually travels). So the GM has determined that only about 7-18% of the females we meet will be dwarfs. - He has this from an advantage limitation, where it gives a 35% cost reduction. However this is a disad so it will most likely not apply.
3. This is DF so much time will be spent in dungeons where there aren't exactly bundles of Dwarfen females to hit on either. As such the disad will not be active for much of the time. - There is however some gaming that takes place in towns.
4. And our current base is a town where a dwarf female is present, and my character has already bedded her. This might cause a problem, since her father is the partys main buyer of loot. As such it is not a disad wthout consequences either.

So far we have put the price at -5. That is a combined reduction of 65% (from the original 15 points).
Any help at attempting to price the combined reduction (or even just a "well those 5 points seem fair" would be appreciated.
Thanks