I dunno, on first read I was thinking what a er barsteward Jack is, and I'm not sure that I don't still think that.

Sounds a lot like she's not aware of the narrator and Jack being lovers yet they must be friends for her to make that request. If there was already some threesome situation then surely they should have discussed a marriage between two of them? It sounds pretty heartless not to have especially with the avoiding.

I'm hoping she's aware she's going to be shared, or is Jack implying that its he himself [Jack] that will now be shared ie entering marriage but planning to keep pov character on the side :(

Dunno, don't think I can like this Jack.