The pics are a little hard to make put for me to really see if there might be anything to date the pendant but from what I can tell you have a heart pendant outlined in rope or braid with a kings crown in the middle of it.
Symbolically I believe the heart represents the obvious love, the rope the joining or bonding properties of love and how the braid is stronger than the strand (ie stronger together) and the kings crown... it's hard to say but I would think it would traditionally represent loyalty or possibly it was his pendant and it just represented the masculine half of the whole.
If there is any sort of other markings post up a pic where it can be seen. Cool find.