Narcissistic parents may feel that they are losing control over the child and their relationship with them when they start dating someone new.
They may feel like you are choosing your partner over them, and this can trigger feelings of insecurity and jealousy. Narcissists often have difficulty handling change, so they may try to sabotage your relationship in order to maintain control.
In some cases, they may even go so far as to try to turn your child against you or your partner. If you are in a relationship with someone who has narcissistic parents, it is important to be mindful of these potential dynamics.
https://fahimchughtai.medium.com/6-reasons-why-narcissistic-parents-hate-your-partner-c0127b5d32cf
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