jimochi:
I forgot to add the greatest love to my list but I watched it too thank you
Ok I went to your " plan to watch" list and the hero in Protect the Boss is quite jealous and the hero in The King's Woman is obsessive and possessive. Neither of these are my favourites, despite my love for obsessive MLs, but they do feature what you have asked for and you have already watched all of my favourite obsessive guy dramas :-)
Oh also New Tales of Gisaeng has an obsessive guy, I am still in the middle of it, so not 100% sure just to what extent. However, beware it's a commitment, as the drama is over 50 episodes long and it takes a while for him to get obsessive, plus the romance isn't always in the centre of the action, thus patience is a must :D