Don't make changes to agreements while in NRE.
DO schedule extra time with the partner you aren't caught up in NRE over.
Don't break boundaries/agreements.
Do schedule times to not talk about the new partner.
Do schedule time to talk about all the reasons you adore the partner you aren't in NRE over.
Do romance the partner you aren't in NRE over.
"Love As Thou Wilt"