Do you still befriends with your exes? Is it normal to be friends with exes?

My boyfriend is close with all his exes especially this one ex he dated for 5 years. She’s a married woman with 2 kids (yes, they were having an affair before).
There’s something about him and this woman. I have a feeling that she’s still has a feeling for him too and my boyfriend sometimes still calls her ‘baby’ which is so weird in my opinion.

Do you all still befriends with ur exes? Is it normal?
Do you still befriends with your exes? Is it normal to be friends with exes?
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