It's not clearly stated, so you may want to try your luck, but I really don't think your j tix will give her access, but seems you may be able to purchase access?
assuming you have priority pass, the primeclass lounge is great, and if you ok with being seperated, while she enjoys her stay there (which to this day I think it's the best priority pass lounge I've ever been to) just hop on over to the Oman air J lounge to have thier better food.