Wolfyrinn said:FLOWER SYMBOLISM- This is perhaps the most important point that proves that her heart only belongs to eren. On her grave we see 4 roses, now interestingly 4 roses means that “nothing will come between the two of us”. not only that, we also see her giving a single rose on erens grave, now a single rose means “you are still the one”. I mean isn’t it clear enough to state that she is single, do you really think that isiyama has drawn it by mistake, this is not a kindergarten drawing where you draw anything you like, this is a manga that millions will read, so there is no room for mistakes. Not just that during her deathbed we see Mikasa surrounded by lilies. Now interestingly white lilies represent the purity and Virginity of a woman. Meaning that Mikasa died as a virgin. Isiyaama is trying to tell us that she remained single the rest of her life.
Bandages- Another important clue that proves the adoption theory of Mikasa is the bandages. Her mother told her to pass on her symbol to her children but we clearly see that she still has bandages hidden which implies that she never had any biological children. If isiyami wanted to show her married then he could have removed the bandages from her hand, but he deliberately did not to indicate that she isnt married. These are so many hints that prove she isnt married or had any children.
The scarf- In all those 8 pages we have seen Mikasa wearing the scarf that eren gave her. That scarf serves as the bond between her and eren. He might be dead, but he is still within her heart and Mikasa will always cherish it. If she would have married some other guy then why would isyama show all the pages in which Mikasa is present are next to erens grave but not with her husband. Even during her death, she held her scarf with her implying that she will never forget her loved one which is EREN YEAGER. Remember the scarf also serves as an engagement ring which is clearly mentioned in the guidebook.
Erens grave- After researching a lot we got to know the translation of what was written on Erens grave. it states “ here forever, resting peacefully, my most beloved”. These words indicates that even after his death she still loves him.
Even in the AOT guidebook its stated that Mikasa's martial status is single.
Actually, its not confirmed whether its Jean, When asked, Isyama said that he purposefully didn't show the guy's face beside Mikasa on purpose cuz he wanted the viewers to decide, ntm, in the lastest manga panels Armin was shown with the same hair-style, so some say its Armin (Idts cuz Armin's with Annie).