I'm playing a male trooper so I have not had to deal with this exact problem, but I'm thinking that in real life this works so try it in game. Get a water spray bottle and every time he does something you don't like spray him in the face with water. It works on RL cats so I'm thinking it should work on him too.
Lol, I like this... only problem is that my cat is stupid so I end up doing the face-spraying 3 or 4 times a week
But as with a lot of RL relationships, if you do not nip it in the bud early (I think the cold-hearted ***** dialog on the necklace is probably the last "no thanks, affection but no romance" option you get), then later down the line you end up hurting the other person more than if you had said something earlier.