violating the space-time continuum to get laid

MC accidentally hecks up his sister's game, gets caught trying to fix it, and gets dropkicked so hard it yeets him into the game world as a minor antagonist. All he wants is to be left alone and hopefully go home once the game ends, so why are all the male leads following him around like he's the heroine? And why does it look like the heroine only has eyes for his (female) cousin?

Truck-kun bodyslams MC and his attitude into the world of a novel, where he wakes up as the shrinking violet fiance of one of the villains. The gods want him to save this world, so obviously step 1 is making sure his contract husband-to-be doesn't turn to the dark side!

This would be a lot easier if his fiance was a little less paranoid. Or if the gods would give him literally any help at all. Also if he and his fiance would stop obliviously falling in love with each other.