6 month going to try formula

So my baby girl just turned 6 months on the 20th. My fiancé wants me to try switching to formula. My daughter has always refused a bottle. We are breastfeeding and doing solids. We can’t go anywhere longer than 2 hours without her screaming and needing to be fed. Or sleep without a comfort boob every 4hours. I totally don’t mind!! It hurts that he wants me to stop. Well I told our pediatrician at our appointment today and she gave me a sample of Similac saying some babies won’t even take formula this late. And if I needed to be out for 4-5 hours to have someone give her water and solid foods. Has anyone done the transition to formula this late? We bought a sippy cup to see if she will try that.