“If you can’t regulate your own emotional temperature, you’ll regulate everyone around you to keep yourself comfortable.”
― David Schnarch
This has the effect in relationships of enrolling your partner(s) in a stifling, contracted and stale relationship as the mandate is not the relationship but the need to control one persons emotional equilibrium. Unfortunately the more your partner is conscripted to soothe your emotions and provide the reflected sense of self your need, the worse things get: as one partner's needs are sacrificed to the other partner's fears. Then too the fear can arise that, if your partner develops the ability to look after themselves, then they wouldn't choose you.
The key to breaking this is to develop as much emotional autonomy as possible: that is develop your ability to manage your own emotions, anxieties, feelings and thoughts (Self-Soothe). By Increasing your ability to Self-Soothe, then it is one of the kindest things you can do as you are giving your partner the chance to reclaim their sense of self and their own life.