Natasha/Darcy/Clint
Darcy always thought her soulmark shape meant that her first contact with her soulmate would be a hug, understandably, considering it was a pair of arms across her shoulders and back. It wasn't until her fifth movie night at the tower that she figured out it was not one soulmate but, in fact two soulmates.
Darcy sat on the couch waiting for everyone to filter in when someone landed on it right next to her.
"Clint!" Darcy nearly yelled, "Watch where you're landing!"
"Sorry," Clint said sounding not sorry at all "but we thought you looked kinda lonely sitting here all by yourself"
"We?"
"Yes, we" came from her left as Natasha slid in next to her, sliding her arm around Darcy's shoulder and was mimicked by Clint a second later.
They all froze in place as a feeling of what felt like static but not really crept across the parts of them that were in contact, and the warm fuzzy feeling of a soulbond settling into place in the backs of their heads.
"Well…" said Natasha.
"We did not expect this" finished clint.
"But we're not complaining" they said in unison.
Darcy wasn't complaining either, the knowledge that her soulmates wanted her as much as she wanted them, even before they knew they were her soulmates warmed her heart.
"Soooo" Darcy drawled while cuddling into her brand new mates, "are we going to my place or yours after the movie?"