My partner and I have recently submitted the I-129F for our K1 visa.
I realized this week that I don't know whether my statutary cohabition ('wettelijk samenwonen') with my best friend here in Belgium would be considered an issue by the USCIS or US Embassy.
This entails the following: "Two people who are living together and make a declaration of statutory cohabitation to the municipal authorities of their municipality of residence are statutory cohabitants. That declaration provides them with certain legal protection. Statutory cohabitation is open to all people who live together in Belgium. It is therefore available to both heterosexual couples and homosexual couples. It is also possible to cohabit, under the statutory scheme, with a member of your family or with anyone with whom you have a relationship without sexual connotations." more information can be found here: https://www.belgium.be/en/family/statutory_cohabitation.
Since it is mentioned the cohabitation officially ends when one of the cohabitants gets married, I assume I'm in the clear. But I'd love to hear from others that might have gone through a similar situation?