Ending strongly suggests that the boyfriend regretted it and never lended his girlfriend again. (Bull contacted him couple of times afterwards but the couple never answered him) Well. I understand. She literally told the bull that the sex was better than with her BF. However the BF was surprisingly clever for hentailand -> usually we would see the idiotic BF lending her more and more until she would be stolen for real.
So, the boyfriend was very enthusiastic but always doom scrolled looking bored while the gf fucked... then as soon as she said it was better with the bull he calls the whole thing off. I'm not sure what the point of the story was.