An affinity in main [[fighting]] skill does not seem to have any effect, except when skilling up to 20 with a practice doll.
If you lose all your affinities, you will get a new one in a random skill in roughly 1 - 3 weeks a undetermined amount of timeranging from a day to several months.
Additional affinities may be gained by killing other players in combat, providing the following conditions are met: