Pretty sure the dev intends to implement multiple spouses in a future update however IDK when.
The courtesans, your working girls, are ALL on birth control so you can cream pie them to your heart's content but they will not get pregnant. That would cost them their job and you your profitability from having them working. You need every swinging tit and dripping quim in your employ ready to meet your client's needs every day. Not only can you not afford to have them get pregnant, the game will not allow it. You can visit every one of the girls and cream pie that pussy every single day but they will not get pregnant. That is not part of the game.
The only woman in the game that you can impregnate is your spouse. So, have sex with your wife often to keep her pregnant and you will soon have multiple children. I have four at present just with the visits I have made while actively playing the updates. Once the update is complete, I save, close and await the next update. No hurries, no worries. If you want many children you can always do the repeatable events and have sex with Sophia every day, even between updates. Her cycle will continue as long as you are playing and is not affected by the amount of other content remains in a given update. You can just keep going like the Energizer bunny if you want. It's a fairly regular cycle... You have sex with your wife, she gets pregnant, you can still have sex with her until she gets close to delivery, then the baby is born, Sophia goes to the family's suites for a short time, has her period when she return and once that is over you can start all over again. Pretty sure that you can generate a new child about once every other in game month, maybe a bit faster. It's on an accelerated pace to keep the game from dragging.
To get to the marriage sex as soon as possible, take advantage of both conversation options each day and give her gifts. Sophia's best gifts are hot sauce, fresh strawberries and the towel, in that order. Hot sauce is her favorite and worth more affection points. You can also take advantage of the Play option depending on how you want your wife to act around you. My Sophia is submissive and loving. You can also choose to have her be dominant and/or breeding crazy. You can try different options and can always change those whenever you want... just takes a few days making the new choice to see the big difference.
Hope that helps, my friend. Adventure ever on, Phat
PS: One last hint... You exchange your accrued affection points for the next level of intimate contact, you also need to have the same amount or more left over after that exchange to perform said intimate contact option. I don't remember what each level cost but I can give an example... the option to which you want to upgrade costs 800 affection to unlock... You ALSO need 800 affection remaining to actually perform that action. The upgrade costs you affection points but as long as you have sufficient affection remaining on your score then you can have that upgrade option as many times as you want. Yes, even multiple times per day. I made that mistake once with the BJ option. I saved affection as quickly as possible to unlock the action but didn't have enough left over to actually perform the action... lesson learned. I made double sure I had at least double the required points when upgrading to actual sex! Hahaha