What would you do if you found out the girl you've been dating is 3 months pregnant from her ex?

Not pregnant by the way but I haven't had a period since my ex and I did the deed in January. I've taken 2 tests that came back negative but I know I should probably go to the doctor to confirm which I will soon.
What would you do if you found out the girl you've been dating is 3 months pregnant from her ex?
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