To get Dulrig's available heart, mine 5 emerite beforehand then take him on the Munbury trip.
Stay with him the entire time, and do the following options:
- Watch him and give a rimjob
- talk to him repeatedly (he will say go away, don't), You will then get the option eventually to protect dulrig, which you need to succeed
- finally at the end put 5 emerite in his bag
That should be enough to acquire the heart, it took me forever to figure it out so I had his like pretty much maxed from giving him Lube daily and the erotic book gifts. Lemme know how it goes!