Over the years, the majority of the women I've had sex with were using some form of birth control at the time I was having sex with them.
I think most men who seduce women regularly will end up with a good number of women using birth control.
I've nutted inside about 10 women in the past couple of years.
I follow Iron Rule of Tomassi #7 about always using protection.
My closest experience to this is ejaculating inside the vaginas of multiple women not on birth control while using a condom.
This is higher risk than doing this with women who are birth control users. I have more peace of mind ejaculating inside the vagina of a birth control user. I do not worry that much about doing it inside the condom when a woman isn't on birth control. Condoms are effective.
I have ejaculated inside women not on birth control near ovulation while using a condom.