NoFap and Threesome w/ my GF and her friend

Guys, I want to take a question with you.

First of all, I want to apologize for my English, that's not my native language.

I'm starting NoFap now, actually, I've been there for 7 days without PMO, and I wanted to know the impacts of the real sex with my girlfriend to the goals of NoFap.

In those 7 days, I felt more active and much more motivated, however, I feel that I have low libido.

My girlfriend proposed to me this week to do a threesome with her friend (we'd been trying for a long time and she just ran into it now). I am afraid of the impacts that this threesome can cause and also fear of having ED during in sex.

I'm new in the community, that's why i'm doing these questions that seems easy to you answer, but I didn't found any topic related especifically about the "odd sex" (like threesome and fetish, in general) can cause to the NoFap.

Since now, I appreciate the attention.