Beppito

BEstfriends
Partners
Procrastinating officially marrying each other

ITO (man) ITA (woman) -- term of endearment

Jack and I have lived together happily for years and plan to be together forever; he is my BEPPITO.
Jill is my BEPPITA and will someday be my spouse.

Beppito is for a man; Beppita is for a woman. Appropriate for any combination of men or women: man-man, woman-woman or man-woman.