I suffer this SO badly... At least before, if the only friend I have who has a stable girlfriend was unavailable for any reason, I had friends within walking distance to visit, but now I'm at uni he's the only friend I have who likes just hanging out. Call it chavvy, but we find just hanging around outside pretty fun.
But recently especially, I've been walking with the pair of them from the campus, hanging out with them at a pub, whatever, and something will suddenly start an arguement between the pair, and it instantly makes them separate from EVERYONE, and especially when it's just us three, I look like a total tool trying to keep away while they argue over something stupid like "You said you were coming cinema tonight YOU'RE A TERRIBLE BOYFRIEND FOR GOING BACK ON YOUR COMMITMENT" so I don't get pulled in, while simultaneously trying to stay near incase it dies down and I feel safe to enter their personal bubble again.
I swear, the amount of arguements between couples I see, it's why I don't actively look for a relationship these days. I don't want the bullshit, and will likely dump anyone the instant I start getting bullshit from one.