Another thing might be what 'sources' for interaction you consider, dates/hookups/meetings vs. people you already know. Lots of people meet each other by proximity, like at work, special interest groups (like sports clubs), volunteer work, conferences etc. If you consider what friends you might have and how you got to meet and know them, the same source might be a place to find someone to become more than friends with.
Lastly, is there a risk of forcing the issue, "looking" for someone to play a specific role instead of having a single interaction grow into more interactions, and then get to friendship/intimacy after that etc. Most of the long standing relationships around me (and my own) are based on organic growth.