Yes, the plot is flimsy. And yes, the main love interest is kind of an ass. But I have to say I did enjoy this, although I can't tell you why. I'll try nonetheless.
I liked Sebastian. I liked the comedy of errors aspect with the twins (although despite Bronwyn being in Kent, did anyone think to consider she might not want to be killed off, what if she ever wanted to return to London?) And you can't have identical twins that are opposite genders. But anywho.
The emotional turmoil of Sebastian's discovery really hit me hard. I think it was reading Sebastian's side of things, and how upset he was but at the same time how strong he was. It also worked for me that we did not see Anthony's POV in this case, so I really related with Sebastian and was just as in the dark as he was.
I do wish that Anthony wasn't quite such an ass though. Yes, he was sweet at times. And yes, he seemed to care for Sebastian. But the childish pouting and lashing out was really unattractive. It reminded me of abusive relationships where one hits the other and then immediately is super apologetic and all "It'll never happen again! I just love you so much!" I'm OK with them needing to have had a few fights prior to the big one, I get the build up and culmination of events. But it was one too many for me. And one in particular made me question whether Sebastian should be with him at all.
One thing that could have pushed my rating up were steamier sex scenes. They weren't fade to black or anything, they were just kind of... meh.