My first question to you is: Are there their children from your prior relationship that you are now co-parenting? If the answer is no, then it’s simple, it is no longer any of your business who your ex is with. They are an adult, making their own choices in life. You have no say in the matter.
If the answer is yes, you have children, then the first step in answering this question is for you to examine the reasons you are thinking this way. You must be honest with yourself and discover what is behind these feelings. Is your disapproval more of a personal dislike, or an emotion rooted in jealousy, insecurity, fear? Or is it based on real knowledge and substantial facts that this person is not a positive influence for your children? Does this new relationship endanger the best interest of your children in any way?
For many mothers, the sudden introduction of another would be mom to their children can cause darker emotions to surface. They may fear that their children may like this other woman a bit too much and they might be replaced. It’s a common worry, even normal. But the truth is, if you have been a real and loving mom to your kids, no one will ever replace you in their hearts.
If – during your honest and forthright conversation with yourself – you find you aren’t over the ex and that’s causing resentment, then it’s more your problem and not an issue with the new partner at all. Even though it’s hard, you must get past these residual feelings. If not for yourself, then for your children. If your partner has moved on, so must you. Hanging on can be self-destructive and unhealthy.
Do you trust your children’s father/mother? Do you believe he/she would do nothing to hurt your children? If you do trust them, then you have your answer. If you let these feelings of disapproval undermine the trust between you, it will make co-parenting difficult. In turn that will affect the children.
If there are concrete reasons behind your feelings, such as clues that your children are in danger, or being around the new partner is not in your children’s best interest, seek professional help and take immediate action to protect your family.
The main thing to remember is that it’s never about you, the ex, or even the new partner. It’s about your children. If there are no children involved, then get on with your life and forget about the ex and what they are doing or who they are doing it with. You’ll be happier, healthier, and can focus on finding a new relationship yourself, if that’s what you desire.