Was Robb lying to Edmure?

[Agent 326]

Back in ASOS I couldn't help but feel as though Robb was shaming Edmure into marrying Roslin Frey by telling him that if you didn't attack then Tywin would've come west and then we would kill him and destroy his army, so that was Stannis wins during the Battle of Blackwater Bay. I see too many holes here to think that this was actually the case. First thing, what about Roose Bolton and his host, where they supposed to do anything, and what if they stopped Tywin, then what? Second, Robb leaves at about the time that Catelyn leaves, and Renly was still alive. Third Robb was conspiring with Stannis, wait what? Because otherwise how would Robb no that Stannis was attacking. Fourth what if Tywin goes back to King's Landing. Fifth, what about the Tyrells, what if they smash Stannis's host, they still likely would've won. Sixth, Robb had his forces spread out everywhere, so what if Tywin does come and is able to wipe them out. Seventh, Robb didn't tell Edmure why he said to hold Riverrun, why not tell him why. Seriously what would Edmure gain from betraying you, and he is your most powerful bannerman, because he is the lord paramount of all the Riverlands, and also he is your uncle and you saved his ass at the Battle of Whispering Wood. Eighth, Robb went west to take out Stafford Lannister's host, he likely is staying their for loot and plunder, why not, the Riverlands and the North aren't producing much food and the Westernlands has lots of gold so you can trade with the Free Cities, Hire Sellswords, etc;. Ninth, Robb says that the Blackfish's scouts how haven't been in the Westernlands for a little over a month and they have found a place that Tywin hasn't in 15 years, and Tywin would be foolish enough to go their. Tenth, if Tywin did come west it would've been disastrous for Robb, because he is wounded at the Crag, while his host is scattered and remember the Crag was easy to take. Eleventh, Robb is a fifteen year old (who has been raised to put honor above all else) at this point in the story which explains the many holes of the lie.

What are your thoughts on this theory?

Don't be mistaken though Robb is my favorite character that has ever been in ASOIAF but still, not one of his best moments. Also this is the kind of cruel irony that George R.R Martin loves, kind of like Theon wanting to check under Crowfoods eye patch to make sure that it is just an empty eye socket, when in truth he would be completely horrified when he finds and obsidian eye staring back at him. The one time Robb lies, it gets him what he wants, and it gets him killed.