Funny thing is, in those olden times, legit samurai can basically have a wife and a/several concubine(s), sometimes the maid or the wife's handpicked girl.... for days when the wife is 'unavailable' or if she's barren... hard to test for fertility (male or female) then...
but this story? they haven't even consummated their marriage for unrealistic sake... lol
just make a baby and then make it about their growth as a couple and parents... like Takagi moto one....