How your Fallout 4 boyfriend/girlfriend reacts to meeting your toxic ex :
(multiples may apply, so I'm only going with the first, knee-jerk reaction)
"Want me to punch them in the face ?" : Cait, post-BB Danse, Glory, Strong
Makes out sloppily with you in front of them : Hancock, McCready, Piper
Dresses them down verbally the first chance they get : Deacon, Farenheit, Nick Valentine, Preston
Growls as they pass by (bites them if they get too close) : Dogmeat
Starts stalking them and secretly making their life a living hell without you knowing : Curie, X6-88
Incredibly threatening shovel talk "do not cross our paths ever again" the moment you leave the room : pre-BB Danse, Edward Deegan
You're getting the royal treatment for at least the next week : Codsworth, Kent Conolly, Sturges