If your relationship status change is set to be visible to your friends, then yes, your friends will likely be notified about the change in their newsfeeds.
However, Facebook does not send a direct notification to the other person involved in the relationship when you update your relationship status. The change will be publicly visible on your profile (or visible to the audience you've specified), but it won't generate a separate notification to your ex-partner.
Keep in mind that Facebook's features and settings may change over time, so it's always a good idea to double-check the platform's current privacy and notification settings if you want to ensure your relationship status changes are handled as you wish.