Nutting in bustdowns is a no go.
I've had a lot of sex in my day, but I can pretty much count on one hand the number of women I've shot in and none of them were bustdowns.
She's going go play it cool until that baby gets here then she's going to start having expectations of you that are more than just a passing nut and its going to create problems between yall.
Its evident that she's not to smart as well because you've showed her all the signs that you view her as nothing more than a piece of azz and she still let you nut in her and potentially have gotten her pregnant. Hell she even sent you the calendar of when she's ovulating.
She's a dumbazz, and you aren't helping the situation. Morning after pills, condoms, the pull out method, etc are made for situations like this.