Hi @Lovely34
Your Niederlassungserlabnis cannot be withdrawn for the reasons you describe. If you separate or divorce your husband, you will not lose your Niederlassungserlaubnis. Your husband’s claim to be able to deport you is untrue.
You refer to this information:
I was also informed that the residence permit granted to me can be subsequently shortened if an essential prerequisite for its granting no longer applies, in particular if the family relationship with my spouse or child no longer exists.
This is not correct in your situation. There may be some confusion due to the language or terms used for permits. A residence permit (Aufenthaltserlaubnis) is issued for a certain amount of time. A residence permit can indeed be shortened if the original requirement for granting it no longer applies.
You have what is often called in English a ‘settlement permit’ (Niederlassungserlaubnis). It is unlimited and cannot become invalid or shortened if the reason for granting it no longer applies.
Another example would be a person who received a Niederlassungserlaubnis for work reasons. If they at a later point lose their job and have to receive state benefits, they also keep their Niederlassungserlaubnis.
There are certain specific cases where a person can lose their Niederlassungserlaubnis. Some examples are if a person provided false information in getting their residence permit or Niederlassungserlaubnis, if a person has their refugee status revoked, or if a person stays more than 6 months outside Germany.
Your immigration status is secure and your husband cannot change this.
Best,
Éanna