Unlike Propaganda or Tyranny, which are vices about abusiveness to a partner, Meddling is a character "vice of excess" that sees the partner actually pretending and claiming to be responsible through moral enforcement activity, when in fact, their activity is just activity, self-centered, and to the ignorance of the other partner's rights and boundaries. Then we may use phrases describing this effect as "being steam-rolled" by the partner, or even "gaslighted," made to feel as if we are in the moral wrong, when it is really the partner being such.
In being unjust as a "meddling" partner, such a person is pursuing their own life's goals - their "mission in life" or "purpose in life" to the neglect of that of the other. It is unfair and unjust, causing the other to feel pushed or bullied into "getting with the program" underneath the false pretense of being aligned toward joint goals.
People are usually meddling unconsciously, in the codependent personal boundary state, possibly using the most primitive and childish Ego Defense of all, called, "Denial" - which is like "being caught red-handed" and refusing responsibility for one's own actions, or the defense, "Rationalization" to make intelligent-sounding justifications for why they are steam-rolling their partner or revising history (Learning about the Ego Defenses, you will find them to be a handy, objective measure of a personal character maturity level.)
It is pathologically narcissistic to meddle with the goals of a partner, or to make up one's own laws, limits and policies regarding the relationship from an autistic, "bully pulpit" of destructiveness, "win/lose" behavior pretending (even to one's self) as if they are actually participating in the relationship as a real partner.
The other vice of Justice as a virtue is called, "Negligence," where a person passively pretends to be a partner, while pursuing their own agenda.
As a vice which makes partnership within relationships fail to get to goals, and intellectually unattractive, consider Meddling to be negative in many ways, including in sexual attraction, since it actually depletes the reserves of one's own, or the other partner's masculinity or femininity by tricking them with the guise of teamwork, yet is secretly ignoring their partner's personal dreams that empower the passions, making both partners less attractive, and feeling less attracted back.