More specifically, I find it's a problem if they're not into personal growth and development.
Because if they're not, you're going to become increasingly content and happy in life - meanwhile they're going around in circles, getting disillusioned, and will feel increasingly removed from where you're at in life and will be inclined to lash out at you because of it.
What you ideally want with a partner is two people who can grow and stand side-by-side, supporting each other through life's challenges with smiles - in contrast to a form of co-dependence that topples over once one person is strong enough not to be dependent upon the other.
Well that's how I see it, based on experience, reflection and discussions with others...
"Having understood name-and-form, which is a product of prolificity,
And which is the root of all malady within and without,
He is released from bondage to the root of all maladies,
That Such-like-one is truly known as 'the one who has understood'." (Snp 3.6)
"Whether I were to preach in brief, Sāriputta, or whether I were to preach in detail, Sāriputta, or whether I were to preach both in brief or in detail, Sāriputta, rare are those who understand." (A I 333, Sāriputtasutta)