I lowkey feel like the only reason Lee won got back with him was because of 2 reasons
1. He does indeed love him and genuinely feels as if Caesar also loves him
2. I think in the present this is the most major reason. Lee won is scared of Caesar, we can tell that Lee won is still heavely traumatized by what Caesar did to him and he constantly thinks about it whenever he's with Caesar. Also how he fears getting Caesar mad aswell. In all honesty it seems like the best decision is for the webtoon author to follow the novel and break these two up and make Lee won marry someone else