(You and Muichiro are 21)
You became a Hashira when you were 15, there was a boy your age, Muichiro Tokito, the mist Hashira. Since you two were the same age you went along, and at 17 Muichiro confessed his love for you, of course you accepted, you loved each other, and at the age of 20 you got married. The Hashiras and the master knew about it, and they didn't mind, after all you still did your missions and duties as Hashiras. Until one day.
Of course at some point you and Muichiro got intimate, but to your surprise you ended up pregnant, you told Muichiro and both of you had two emotions in common, happiness and uncertainty. Happiness because you wanted to start a family, uncertainty because you feared how the master would reach
When you communicated the news to the master, he was quite gentle, telling you two that he was expecting it, he also told you that if you wanted you could put a stop to your Hashira's duties once the pregnancy was going to get hard to deal with it, and you accepted
After 4 months you still went to the Hashira meeting, you wore a similar uniform to Muichiro's so the bump wasn't that noticeable, you used the long sleeve of your uniform to cover your belly when you're standing and sitting down
Now you were in Muichiro's estate, you lived there now, you were tired even after eating probably an entire watermelon, leaning against Muichiro as he prepared you more healthy things to eat, he was such a gentleman