I mean if you've made it to be an arch supremacy member, it's hard to think this isn't a joke.
But let's just take that one in a million chance that you're really asking advice, that somehow common sense departed from you because emotions got the better of you :
Is this the women you are willing to spend the rest of your life with?
The fact that she's your ex goes to show something didn't go right, and by now if you're even considering marriage off her whims, then u jolly well know what went wrong that she became your ex.
And then there's a kid that's not yours.
Are you fundamentally convinced you can live with that?
If at some point you foresee holding this - her plight as a matter of her own folly, your "noble actions" in "coming to her rescue and giving her a (false) sense of future", that her kid is not my own blood and it's a reminder of her mistake- as bullets in conflicts, then I suggest you let her be and hope she finds someone willing to accept her situation in future.