From a quick search with google-senpai, there are 51 chapters, (some have multiples x.1 x.2 ... etc)
Also, there are "honeymoon" chapters. Hum, I wonder if they do anything? ( ͡° ͜ʖ ͡°)
Here is the list https://piccoma.com/web/product/16071?etype=episode ('Free' chapters (by free registration) - only go till chap 17 )
You can rent a chapter for free for +71 hours. And you can rent a new one after 23 hours since you will get free recharge after that
but only 1 chapter at the time :'(
(Not sure about details tho, this is how it works for me)
I mean, we get to see the POV of Kiyoshi, but not the Sumi's POV. she is a high schooler who just turned 18, she is pretty naive and all, and the fact that we don't get her point of view makes it harder to get her. I hope she knows what she is doing and that she is also in love. I want them to be happy so I hope this is developed in future chaps.
I know in Japan, sadly women sometimes just choose to become a housewife and don't even get to work or after getting married they leave work and become housewife, that is why she didn't put plans career down. I don't mind the age gap, just 18 is just pretty soon. At 18 I had no clear idea wtf to do, so this big of a decision...