Hi cm3557,
boundaries work not because we explain them to someone who is unable to follow through with agreements. Boundaries work because we have ways to protect them.
One way to think about how to protect a boundary is really starting from the basics - what value do I want to protect? How important is that to me? What am I willing to pay to protect it? The first boundaries are usually the hardest - the learning sets in on both sides.
So what do you control? Can you prevent yourself being pushed? Where? To what degree? Leaving without much ado is often the best for being pushed - let him stew and don't give the satisfaction of a fight.
Same for pull? How does he pull you in? Possibly easier to take measures for you to not be pulled so strongly?
Again the first ones really need some thinking and planning. There is not a one-size-fits-all. The workshop section has material on boundaries that may be helpful.
Yeah, what is pulling in anyways? I think I've been subjected to this push/pull behavior as well... .