I’m kinda happy Sam and Dean are growing up and realizing that they don’t need each other like they did before. That’s pretty damn healthy for what they’ve been through. Besides, they can know that they don’t need each other but still choose to be close to each other even though Sam has someone he cares about now and is attached to.
Personally, I think that would make their relationship even better… the fact that even though they have a choice to not be close, they still choose each other.

But then they’re gonna die. So. You know. At least they’ll go out being healthy right?