Steve has always been the one to lose Bucky:

– in the first captain america when bucky fell off the train and ‘died’

– in the winter soldier when he disappeared at the end and steve spent years trying to find him

– in civil war when he was frozen at the end in wakanda

– in infinity war when bucky turned to dust

That’s why it’s going to be 100000x more painful if Bucky experiences losing Steve for the first time in avengers 4

Especially knowing that Steve probably won’t be coming back like Bucky always has

Bucky would end up losing Steve forever…