100 years in the future? So it's as if someone from our era decided to have a kid with [insert random ass early 20th century historical figure/celebrity] and went "yep, I think they need to know that, let me alter the space-time continuum to be gay". The story sounds too fishy.
The timeline is too weird for the "she disappeared because she went to the future with the baby mama" theory. How come this woman that disappeared ~70 years ago (assuming MC was like almost 40 when she managed to become such an influential figure) is so important to you, girl? You couldn't even have met. What, is she your grandma or smth? Are you the mother of your own mom or something weird like that? I hope that she lied and the gap is not that huge. Give half a century or at least enough so future MC would be an old lady has she not disappeared.
Also, I think that the way this fiancée spoke it's as if she has a harem of sorts and/or it's an arranged marriage because she's someone super powerful. Yuri dictatorship in 2124 ig.
I am just super confused now... Does she plan on coming back to her era and going "nope, I am married with this SuPER inFLUEntiAL figure from the past and we have a CHILD! who's grown so much! so I can't marry you"???? Girl...