So far the differences don't really change the main plot too much, so if you want to stick to the webcomic, it should be ok. I do recommend reading the novel though. It was one of my favorites from way back.
You can enjoy the manga just fine. The manga has changed some parts of the novel there are big and small changes but seems to be going in the same direction. If you don't like to read novels just keep reading the manga only.
But spoiler ahead
This story has rape, Seme is an asshole. if you are not ok with that I would not recommend you reading either of them
I think i have the novel link i saved somewhere... should i read the novel too or just stick to the manga? I saw many said there kinda differents things here and there.. (⊙…⊙ )