As someone who just binged all the chapters up to the most recent chapter 86 of Koi to Uso, let me just say this manga is very frustrating. It's good but it's also very frustrating...
The initial story is interesting. Age 16, you get assigned a marriage partner using genetic, psychological, and a variety of other data (Go Science!) in order to find a perfect match and combat the declining birth rates in Japan.
The art is fantastic, though the trade-off for that is that the chapters are extremely short.
The frustrating aspect is that the MC is so stubbornly in love with Grill 1
despite the fact that the government sent him a notice that he will marry Grill 2.
Problems arise because Grill 1 is also in love with MC, but she tries to do the right thing and keep that as a memory and move on with life. MC ends up crawling back to Grill 1, neglects Grill 2 (Who is extremely accommodating towards the MC and a better choice but just gets tossed aside basically), and MC breaks Grill 1's resolve to do the best thing for both of them so many times. He's so oblivious to what the right thing to do and is making matters much worse. He's made both Grills cry already. MC is a jerk.
Oh and MC's bestie is probably gay for him.