Too-Stretchy Shoulder! Help!

I’ve knitted up a cabled/ribbed sweater for my husband in the following pattern:

k2, p2, 4st-left cable, p2, repeat!

According to the pattern (from Knitty: http://www.knitty.com/ISSUEfall02/PATTanniversary.html), I did a three-needle bind-off for the shoulder seams. The seam came out nice and even, but it also stretched out the shoulder seams! The purl parts of the ribbing are nice and tucked back for the majority of the garment, but at the shoulder, the purl section is no longer “tucked back” and so is adding several inches to the length of the shoulder seam, making the whole sweater totally unwearable! Is there something I can do to make this seam less flexible and shorten it up? Perhaps I can add an additional seaming that would shorten the shoulder back up and preventing it from stretching?

Any advice would be greatly appreciated.

According to the pattern, it is an off shoulder style. You might try cinching is somewhat with twill tape, sewn into the inner seam.

It’s definitely an off the shoulder type pattern since there was no shaping on the body.

I’ve tighted and edge with crochet and I know someone at my Knit Night did the same on a seam. Crochet is less stretchy so if you can crochet across the shoulder seam… probably a slip stitch kind of thing it would probably help a lot.

Maybe crochet the 3 needle BO instead?