If you didn't know the man in question, which would you find more likely: that a woman emptied a condom in herself in order to secretly make herself pregnant, in order to claim alimony; or that the couple failed to practice safe sex correctly (either through omission or due to an accident)?
I have a friend who's a family attorney and I wish he was exaggerating about all the fucked up cases he tells me and his colleagues have. Women pulling every trick in the book in order to have a baby with an unwilling partner (of which include lying about being on birth control, and in one case, digging in the trash to get a used condom and attempting to get pregnant that way) more common than you think. In almost all instances, men are completely blindsided and then sucked dry by the courts.
You don't hear these kinds of talking points from feminists though. Equality in the court system simply isn't a priority to them.
https://en.wikipedia.org/wiki/Reproductive_coercion
>Around 10% of U.S. men reported ever having an intimate partner who tried to get pregnant when they did not want to or stopped them from using birth control. Around 9% of U.S. women reported having an intimate partner who tried to get them pregnant when they did not want to or refused to use a condom.
when male birth control is available things are going to massively change, in a positive way.
In any case, given that it takes few months of trying for women to get pregnant, the lady with this plan would have to expect to empty a lot of dried condoms. Kinda unlikely idea.