I would ask your soon-to-be wife whether she'd be ok with a lab grown diamond vs a natural (and let her come to her own conclusion without mansplaining to her that only morons would prefer naturals).

Some women would honestly prefer a 0.5-1.0ct natural vs a 2.5ct synthetic.

In any case, the ring is for her, so I'd recommend making sure she's on board with what you're thinking.