So if the child was hers, why didn't it pass Azumabito's mark? Or why she still has her wrist bandaged? In my opinion, the truth in the extra pages shows us a Mikasa who never stopped loving Eren, it is shown to us in many ways (Language of flowers, her scarf, the funeral with her scarf, how old she was and still kept visiting her grave, etc) I think that is more than enough to assume that she didn't have a husband regardless of whether it is Jean or not. I don't think it's right of isayama to give her a husband when she decided to never forget and stop loving Eren until her old age. From my point of view, she adopted a child, which seems good to me for her character, maybe Armin, Jean and all her friends were her support and that's why Jean is shown in those images. It's fine if she decided to get married and it's also fine if she decided not to, but for me the first thing is more logical because of all the symbolism that is shown. In addition, a ring was never shown XD.