Hey guys it's me again. I've been going crazy trying to find this fic and I hope you can help me.

The fic was on Ao3 and it's basically what the title says. The boys are in an established relationship but for some reason, I can't remember why, Sam gets it into his head that the only reason Dean is in it is because he wants Sam to stay with him. That he doesn't really want Sam 'that way', but he goes along with it anyway because it's the only way to keep Sam 'happy'.

I remember there was a lot of flashbacks where Sam keeps remembering instances where he thought Dean used sex to 'manipulate him'. One particular flasbackI remember was when they were younger and Sam was complaining about how they had to move again in the middle of the year and basically Dean counters that by...going down on him, leaving Sam all limp and satisfied, so he doesn't have the effort to argue about it anymore.
Basically I remember Sam being very guilty and horriffied by his 'realisation' because he thinks that he basically 'raped' Dean his whole life, when in fact it was the exact opposite. Dean loves Sam and he was in this relationship with him purely by choice, and he starts getting really upset when Sam starts shutting him out.

All I remember is that the story was from Sam's POV and there was a lot of angst and misunderstandings between the boys. And...I'm not sure, but I think Cas ends up setting things straight at the end of the story when he sees how miserable botht the boys are (I THINK. I'm not a 100% sure)

Umm..that's it. I hope you can help me find this fic because I so want to read it again.

Thanks for the help!

EDIT: FOUND in comments!