I think that Mr. Lee and Diesel's relationship is much older than Minsuk and Bexan's. The transformation may be difficult to go through from the beginning, but I can see how it would become even more troubling the longer it goes on and the deeper their feelings for each other get.
Like, losing a friend during the day would hurt. Losing a boyfriend during the day would be horrible. Losing a husband during the day would kill me. That type of thing.
Yea they aren't really gone, but the it's dangerous for a dog living among humans, and they have to hide their relationship from everyone else. They can't say "Yea of course you can meet my boyfriend!...but only during the night....forever.".
But we also know very little about this newfound couple. So we're see how it pans out. I also feel that Minsuk and Bexan's dynamic is completely different as you said. So they may have an easier time with the transformation in the future than the other two.
I think it might one of those person to person type things. Losing your lover during the day implies that you diassociate your lover and the dog. I completely get that, maybe someone would find it painful that during the day they can't hold their lover's hand in the park, instead they hold a leash. Maybe it's my possessiveness coming into play here, but I personally wouldn't mind being unable to tell friends about my relationship due to Bexan's situation. I'd end up revealing it to my family at some point. Well, in Minsuk's case, he hides everything from his family anyway so that probably doesn't weigh on his mind either. Also, there remains the fact that Bexan still behaves pretty human as a dog. In that last chapter, Minsuk easily swapped gears and started petting Bexan as a dog. So I definitely agree with the second thing I said maybe not even being an issue at all, I just threw in a what if problem. Thanks for the cool reply (⌒▽⌒)
I agree with you Tiger Rao. Someone may disassociate between the two, but for me that person would be the same. I don't care about their form they are in.
Or maybe Mr.Lee is a cat person, so he can't love dogs the same way as humans?......Ok, ok, not a dog but a wolf, right? Still, a husky and a malinois.

It's funny. I don't know what to agree with. Some commentors say the love between Mr. Lee and Diesel is much stronger, the two of them hate the sun for "separating" them. On the other hand, Minsuk and Bexan show total acceptance with their situation even after crossing the line so in a way, Minsuk loves Bexan in every way, not seeing any part of him as a problem. So who's relationship is stronger here? Diesel's may be more passionate, full of longing, but have unnecessary complexities, like Mr. Lee hating Diesel's transformation and Diesel feeling bad as a result of it. Bexan's may be overly simple, and cause problems in the future when the to realize just how deep their feelings run.
Nevermind. Imma just
╮( ̄▽ ̄)╭ Young love