Yes, it affects and very much so, it itself excites the whole brain, not only sexually, but sexually for sure too.
It's great for helping to loosen up both partners, promotes greater trust in each other, and allows you to feel your partner more strongly in these moments.
Also, there is an excellent article on the subject
https://www.smokeandpoke.com/blog/can-weed-make-you-horny/, if you are interested in learning more about it and you are concerned about this issue.
I can say from my own experience that pot has helped me a lot in my sexual relationship with my partner, we have become much closer.