Gatcha:
Thanks for the recommendations. I will watch all of them. I have tried to watch Goodbye my princess but got bored after 5 episodes. I should give it another go.
Actually in that drama the ML becomes obsessive only towards the last few episodes. If you watched the beginning you kind of know what is going on, so skip to the last 10 episodes or so ( cannot remember exactly when it starts). I must say I am not a fan of cdramas in general though.
However, I love obsessive MLs and two guys one girl love triangles. Empress Ki is my favourite drama of all.
Ok for intense love triangles with obsessive ML, but no comedy try:
MILD SPOILERS BELOW, they will be mainly related to the ML and FL personality.
Love in Sadness - Obsession from the beginning, but I personally disliked him. The FL is unfortunately weak.
The Last Empress - he gets obsessive in the second half, in the first he is a horrible monster. The FL is very weak at first, but this changes.
Born Again - The ML is one of the most obsessive guys I have seen in dramas, but in a 'I cannot leave her side' way rather then 'I will not let her go' way. The FL is a bit on the weak side though, many hated her.
I second Missing You, here the SML is absolutely crazy about the FL, he plays a huge part in the drama though. The FL is alright.
The Bridal Mask - the SML is cruel and very obsessive. It's a historical drama.
Cheese in the Trap - it's a bit funny, the FL is a regular girl. The ML is cunning and cruel, but obsessive. In comparison to the other dramas mentioned above the ML is a little milder with his obsession, but still enjoyable.
I cannot guarantee that you won't get bored with the dramas themselves, but I can guarantee that they have very obsessive guys that would go to the extreme to stay near the girl they love. In addition all of those have love triangles as I have mentioned before.
Bonus:
My Heart Twinkle Twinkle - the ML is really crazily obsessive and forceful with the FL, but there is no love triangle and the FL is weak. On top of that I found the story a bit boring when the ML wasn't on the screen. It is worth to mention it though, because he fits what you have asked for.