If you still care about your ex, be happy for him and express your honest wish that he and his new love have a long and happy life together. This might be easier if you are in a stable, committed relationship, but even if you are not, remember the announcement isn’t all about you. Put on your best adult face, smile and say, “Congratulations!” like you mean it.

If you and your ex share kids, you want to discuss how things will change and get to know his fiancée when you offer your congratulations, suggest The Wedding Channel. His fiancée will be your kids’ new step-mom, so it’s appropriate that you get to know her and become acquaintances, if not actual friends, suggests step-parenting expert and therapist Jann Blackstone, PsyD. on her Bonus Families website. Start by congratulating him on the news and ask to meet the fiancée for a private discussion without the kids around. Congratulate her, too, and then talk practical changes that will occur. You can ask if she has kids that will also be part of the new family so you know what your kids will be facing.

If you and your ex didn’t part amicably, you might find yourself not wanting to congratulate him at all. Set a good example for friends, family and acquaintances by congratulating him anyway. Try to be gracious and friendly. Perhaps a new love will ease the strain between you and allow you both to lay old hurts aside.

If you and your ex don’t share kids or a social circle, you might have heard the news through the grapevine or social media. If you have a phone number for him, you can phone or text him your congratulations. If you don’t have a way to connect directly with him, you could leave a congratulatory message on his social media account or send it to him in an email. A congratulatory card is also an appropriate way to send your best wishes.