"I want to be with someone who is with nobody else and therefore I will leave you if you have another relationship" is limiting your autonomy. But then again, saying "I want to be with someone who won't leave me because I have someone else" is limiting theirs, too.
Again, I disagree and I don't believe it is merely perspective.
"If you fuck/suck/lick/cuddle/love anyone but me I will leave you" is prohibiting the autonomy of my partner. It is setting a rule for them to follow.
"If you try to run my life, tell me what to do with my time, rule me, oppress me, I will leave" is telling my partner that I am an individual adult and am not applying for a job. It is telling them how I am going to act and that if they want to be in my life they must not restrict me. It is setting a boundary.
These are two very different principles and I hope you see why. One is determining the actions of my partner, the other is determining the actions of myself. One of these is respecting autonomy, the other is not. Note that I am not trying to make a value judgment on what actions are being prescribed, simply that they are rules set to limit actions of someone else.
You can make rules which decide what the other person is allowed to do (You are not allowed to date others) or you can simply state your needs and boundaries (because I'm not comfortable with you dating others, if you do I shall leave)
You just restated the same prohibiting order. The wording does not change it in the least.
and that's the case in monogamous relationship, and in poly relationships too.
On this we agree. Restricting someones autonomy is not an exclusively monogamy issue. This is something that happens in permission based relationships (as opposed to "right" based relationships). I have the right to live my life how I choose, spend my time on what I care to, love who I wish. I have this right and do not require permission to live my life.
In polyamory, some people might say "you have to use condoms with other people". That's limiting their autonomy. Saying "I'm not comfortable fluid bonding with other people through you, so while using condoms with others or not is your decision, if you choose not to, I shall use them with you to protect myself" isn't.
Exactly. One is deciding how I will behave, the other is deciding for someone else how they will behave.
It's about boundaries, and I think everyone has some of them, and we all need to decide if we're fine with our partners', or if we're just not compatible.
Boundaries are decisions about protecting myself. I don't want genital warts so I protect myself. I don't want to be controlled so I don't get involved in permission based relationships.
What you are trying to lump into "boundaries" is also prescribing the actions of my partner. This is not a boundary, this is a rule set by you which decides for them how they need to behave.