I am Rick Grimes' missing hand
I think that Lori should've told Rick that she and Shane had slept together. She's made it worse by keeping it a secret for so long. Not only does it hurt Rick, but it's helping Shane to think that she still loves him/wants him. But that's my opinion.

I agree. But at the same time that’s a hard thing to admit. Also the show wanted to drag it on a lot longer when Frank Darabont was in charge. It was Glen Mazzara (The new guy) who finally had her tell Rick. Now Shane knows Rick knows Lori Knows… Im pretty sure Dale knows because he knows everything. So now it’s going to lead to something very bad.