I don't want to come on my period on my honeymoon how do I delay it?

To delay your period you can use a drug called Norethisterone, prescribed by your doctor.

Norethisterone is essentially a progesterone pill so it overrides the drop in progesterone that would normally trigger menstruation to start. You start taking the pills three days before your period is due, continuing to take them three times per day up until you want your period to start - typically menstruation will start within 48 hours of discontinuing the pill, it should behave as normal too.