Clint Barton knows where his loyalties lie, and they have more to do with his handler than his employer. Phil Coulson takes his responsibilities seriously, and a big part of his job is protecting the agent in his care from any threat to his well-being.
At this rate, neither of them is going to get a date. Natasha Romanov has other ideas, and the only side she's on is her own.
This is the prequel where the secret mutual Phlint pining gets resolved, and I'm really torn whether to round it up. (Yeah, I'm not following my usual habit of going plot-chronologically, mainly because Drew & Shawn led me to read the story numbered 1, and then I have been simply continuing.) The agent-y repression and secrecy all around, the loyalty and conniving, the self-abnegation and Clint's basic expectation of so little… It's absolutely not hearts-&-flowers, and includes more than one physical struggle (Natasha is, of course, part of the process of not letting Clint just leave), but the emotional climax and the denouement change-of-perspective (in more than one sense) are both very satisfying.