when my fiance leaves our 9 month old dachshund whines eventhough im still there.i haven't been around long so i understand him being more attached to her.
Be friendly with him. Entertain him. Weenies LOVE to play and hunt things and play fetch. Just give him some extra attention, show him you're a pretty cool guy too and you could entertain him just as much as your fiance can.
Don't give him extra treats...thats just gunna make him an extra fat weenie Toys, toys, toys!
ok thats separation anxiety. ur daschund shows itself as the pacc leader. in a pacc of dogs, followers dont leave without the leader's say-so. thats where the whining comes in. im not saying dont love your dog just make sure it knows you guys are the pacc leaders. the dog doesnt do anything without YOUR say-so.
when your fiance first leaves try playing with the puppy for a few minutes with its favorite toy. or right after you fiance leaves maybe take the dog for a walk...start obedience training it. or just simply sit with the dog for a few minutes.