I tend to use what they are. If they are my boyfriend, then they are called that. For me I like to stick to the reality of my relationships.
And I'm not sure, but I believe a handfast ceremony is like a wedding ceremony you have with an OSO with family&friends present (if you choose). It wont be acknowledged legally of course, but its seen as a symbol of the marriage officially allowing in another equal partner... I think thats the term she/he meant anyway