Lydia is my Housecarl from Whiterun while Jordis the Shieldmaiden is my Housecarl in Solitude. Lydia was the first Housecarl assigned to me and she'd been going with me on all my quests since then. I understand that I can only bring one at a time but Jordis won't go anywhere. I even took Lydia all the way back to Whiterun, put her in breezehome, and ordered her to wait there. I then went back to Solitude to get Jordis and she's still saying "It looks like you already have someone with you."

Another quirk I'm experiencing with this is that in wearing the Amulet of Mara, all the marriage prospects in Whiterun bring up the proper prompts except for Lydia. But in Solitude it's different. While Jordis brings up the correct prompts, no one else does. And yes, I've definately done the favors required.

Any help is appreciated. Thanks.

Did you give Lydia the dialog option "It is time for us to part ways" or whatever, and she says "OK I will go back to Whiterun and eat bread while staring at your bed?"

No. I did not. But that was a prompt option. I didn't click on it because I was afraid it would mean I'd fired her. Now I know that's not the case. Very cool. Thanks for you help.

If you only told her to wait then you haven't dismissed her as your follower and thus can't take another... You have to tell her it's time to part ways and she'll go back to breezehome...

And as far as Lydia not bringing up the marriage prompt... She's bugged... Without console commands she won't marry you as she's supposed to...

Ah. That explains it. I did what you suggested in terms of the part ways prompt and it worked but the marriage thing failed again; but at least now I know. It's not that big of a deal. There's a lot of other solid choices, although acidentally prompting Farkus while wearng the Amulet of Mara was kind of creepy. He stepped between me and Aela as I was testing out the amulet for the first time. Eww. Not that I care what anyone else does, it was just an unexpected weird thing for me.