It's hard to define.
My exboyfriend is a close friend. We were in an open sexual relationship and roommates for 4 years. But, our career paths diverged, so we "broke up" in terms of sexual relationship and roommates.
However, we remain close friends. He visits, stays the night at our place, joins in holidays periodically. We've been close for... 19 years.
My husband and I have been married for 14 years, together 15.
My boyfriend and I have been best friends for 19 years, sexually involved off and on over the years. He moved in with us 10 years ago and we committed to an "official" dating relationship 3 years ago..
DH, bf and I are raising the last two of four kids. They are 5 and 12 yrs. They both helped raise my oldest who is now 21.
I don't see us ever "breaking up". There may be a change in household structuring-but as far as being a family-we'll always be family...
"Love As Thou Wilt"