That kind of security isn't really created with a spell.
However, if you two are capable of it, I would suggest a date night.
Get on Skype or some other webcam option, have dinner together, watch the same movie together, etc. Try to make sure you won't be disturbed by anyone for say..3 hours. Just you two, the power of the internet, and the desire to do something thoughtful despite the distance you are encountering.