Over time, your lover, especially, has begun to realize that your relationship is more emotionally taxing and unstable than they thought, and that it's keeping them from progressing as an individual. They experience intense highs and lows with you, and they might never feel placid when you're together. Having a sense of comfort, familiarity and support is an important part of the foundation of a relationship, and this one might lack in that department.
The sense has been growing that there's an emotional imbalance between you. You try to use strong feelings and self-expression as leverage in getting your way, and your lover feels as if they can't be themselves in the face of such powerful emotions. If they're ordinarily a reserved or shy type, this effect can become especially pronounced. Your relationship could become off-kilter because you're taking up all the space while your lover shrinks back, afraid to assert themselves. Don't let this happen! Find a way to be completely aboveboard about your emotions, your needs and desires, while still listening to your lover and committing to at least trying to meet their needs. That way, you don't have to resort to emotional blackmail to get your way. If you find yourselves mimicking a monster and a mouse, take it as a sign that it's time to get things back in balance between you! You can both get a lot farther along your respective life paths if you can do this.