I would really recommend the books since they are amazing and they are not all about romance which is good. There are battles between empires and kingdoms, there are sarcastic and mournful moments. The author of the books, Andrzej Sapkowski made a whole world brimming with cities, villages, towns, kingdoms, empires and locations such as Brokilon or Mahakam. All these kingdoms and characters have history behind them full of battles, romances, political intrigue and important events. I am saying that romance is not the only reason to read the books, but it doesn't mean its bad, its actually amazing and one of the reasons the books are so amazing.
The books describe Geralts and Yennefers relationship mainly. Its stormy and full of quarrels. They often leave each other and go their own ways but they always meet each other again which could be a result of a spell, at least in the beginning. Their relationship grows in time and they start to love each other more and more. Their relationship is deep and stretches over the whole books. And there are a lot of moments between Geralt and Yennefer and thats why people that read the books often pick Yennefer when playing the games . Since there are a lot of moments between them with interesting discussion and it really shows their characters.
While with Triss its not the same. Geralt never has a relationship with Triss. They are rather friends who help each other. There are complexities since between them. Triss wants to be with Geralt but Geralt never sides with her completely since he has his attention on Yennefer most of the time. But that doesn't stop some romantic moments between them.
Its not the same as in the games since in the books it is focused mainly on Geralt and Yennefer.and Triss sometimes intervenes but not nearly enough to create a choice for Geralt like in the games. But i prefer it this way as it always sounds like Yennefer and Geralt were meant for each other. You get to see more of them.
There are also short romantic moments between Geralt and Sorceresses as you probably suspected. Like with Lytta Neid or Fringilla Vigo. But he just goes with them in Yennefers absence when she is not there. And this does not feel like cheating since you know that Geralt loves Yennefer truly.
Overall, the romance in the books is phenomenal and greatly written. I recommend reading the books for multiply reasons but this is just one of them.