Thanks everyone, but I was looking for examples from your lives and how you expressed your boundaries in word form. I like what Learn2Live shared, that was kind of what I was looking for.
I never set boundaries with anyone, not just my AH. The friend I mentioned above, I cut off my friendship with her without warning and she is now befuddled as to why I don't talk to her or get together with her. She's also the one who got on my case about the airbag thing. Anyway, I guess I feel that if I set a boundary with her in the first place, would that have possibly saved our relationship and maybe allowed our relationship to continue. Now, in hindsight(I actually haven't spoken to her in a year or so) I see that she was a toxic person and that I made a good decision but I still felt guilty in HOW I ended things. Basically, I chickened out and ran away. Guess, I'm just looking for suggestions on how to express my boundaries and how to make sure I set them in the first place.