<human>: First things first, the three guys involved, F, S, and me, are gay.  However, the problem isn't strictly about gay couples so I'm posting it here. 

Me and S are very close friends with benefits and also flatmates for the last three months, because we want to live together, and not out of necessity. Both of us are friends with F, but S is closer to F than I am. In fact, F had first introduced me to S almost a year ago because of our similar sexual interests. I've known F for a bit more than a year and S knows him for  a little less than a year. 

While I'm definitely not ready for a relationship with S, I casually mentioned it a few times and he flatly declined it. One of his two reasons is that F had asked him out first and he had declined him too, and doesn't want a relationship with me because it would hurt F, the guy who had introduced us in the first place. He went on to say that F should never find out that we're together. It is true that F is an immature guy and it may hurt him a bit to learn that. 

While that's a valid concern, I don't think that should be a reason to not have a relationship. He does have another reason but I asked him and he said that in the absence of the other one, but would still decline to avoid hurting F. 

Does /r/Relationship_Advice think that is a reason to not have a relationship? I would like to hear arguments for both the sides. 

I'm not sure if I want a relationship with S but I would like to have that thing out of the way. Thanks!

Give me a shortened version of the text
<bot>: Gay best friend with benefits and flatmate doesn't want to have a relationship with me to avoid hurting a mutual friend who had proposed to him earlier, and had introduced us.