It is important to appreciate that just because a parent has adjusted to their separation and has a new love interest, it doesn’t mean that the child has adjusted and is ready for their parent’s new love interest.
Even if a child appears to have adjusted, the introduction of a new love interest may spark some feelings by the child. That the new love interest may thwart even the smallest fantasy of their parents getting back together, which then makes the new person a threat.
Because of all that, it may be helpful to introduce their new love interest first as a friend, not even a special friend.
During all your time together, particularly in the beginning, resist sleepovers as well as open displays of affection. You want the child to get to know this new person without any expectations that they too must form a relationship with him or her, and without provoking concerns that this may thwart their fantasies or create a loyalty bind with the other parent.
In a phrase, it is helpful if the relationship between your new love interest and the child develops organically. That means that they get to know each other gradually and that the new person doesn’t assume any special role with the child as a matter of the parent’s demand or requirement.
Hopefully before, but at least somewhere near the beginning, you can similarly inform your former partner of your actions and that you are taking it slow so that your new partner is not taken by surprise by your new relationship – therefore creating a negative feedback loop to the child.
Many parents think they can do as they please, and that what they do in their private life is of no business to their former partner. Actually, while on one level it is true, on another there are still different kinds of connections, and to the degree to which we understand and account for those other connections, the introduction of a new partner can go easier and more successfully.
If you are in a complex situation and have concerns about the introduction of a new partner to your children, seek advice. Given each situation is so different, a counsellor can help you fine-tune a strategy better suited to you and your children. This is so important because if the new relationship does not work for your children, it can be distressing for everyone and derail your new relationship too.