After the shock of all the negative feelings being dredged up about everything else, that's almost a reasonable reaction.

Jeez, is there anything not terrible that's going to happen when they meet face to face?  One starts to wonder if they could really reconcile their love after all these horrible things.

Oh, yeah, yeah.  I remember now.  My bad.
Still though, that'll be some great conflict, considering the Mercers veer away from outright killing people.

As an idea for how they start coming across each other, I'm thinking Jonathan or Eleanora spots a member of the Reese clan doing their thing with luring people away.  They don't have to be caught in the act, because most of the time vampires know other vampires when they see them.  But one of them reports the vampire to Elizabeth, and they start with their normal protocol for dealing with other vampires in their territory.  Of course, it gets complicated when the Mercers find out they're dealing with a whole clan, and even more complicated when they find who the leader is.
Have you had any ideas about it?