Boundaries are something that. while able to evolve, must be frequently checked and honored over time. Just setting them once doesn't give someone the space to drift away over the years - it requires frequent "inventory checks" of whether or not the agreements are still being met by both partners, and then having the courage to say "This wasn't the deal," and revisit over time - as hard as that may be.

I believe a lot of people get stuck in negative relationships because the goalpost moves over the years due to one person pushing it just a little bit more, and more, and more...this is why we must honor ourselves by being honest about what we're seeing, when we're seeing it, no matter how long we've been with someone.