Idol Yamerukedo Kekkon Shitekuremasu Ka!?

Idol Yamerukedo Kekkon Shitekuremasu Ka Manga :

Sato Itto, an ordinary salaryman, has been shy about love due to an old trauma. Then one day, a reunion is held for the first time in several years. While they are having a good time talking about the good old days, suddenly Hebo, who has become an idol currently on hiatus, decides to attend the reunion!
Sato is upset to see Hebo, who was his first love. He manages to get over it with the help of alcohol, which he does not normally drink. When he wakes up, he finds the two of them naked in the same bed. As Sato desperately tries to recall his memories, Hebo shockingly says to him...!
"Marry me..."
What will happen to the marriage between the two who have no experience with love...!?