First 2-3 episodes were quite promising. A love based on DNA compatibility. But then the writers introduced telepathy between partners!!! Give me a break. Good thing that they didn't introduced teleportation, just so you can go where your loved one is.
Then there are way toooo many side characters. And of course we had to have a killer, cause 4 couples were not enough. Some relations were interesting (doctor-firefighter) but most were boring and annoying.
The series is too long (8 ep max would have been enough) and by the time I got to the ending I was pretty bored (and I dropped this series for a couple of weeks).
A good ending would have made it more bearable but the ending is an open ending, hinting that the ML will lose his eyesight or they will break up. And the SFL... she is something new at he end of the series, not mono, not polyamorous, something only she knows what she is. And the SML is with her, smiling like and idiot, God knows why, cause I really don't.
The main story had potential but it quickly faded away.