To date no one has has met my minimum long term relationship criteria.
I'll date ANYONE who is physically and sexually available, has a greater predicted lifespan, baggage free (not specifically the target of powerful law enforcement agencies or organised criminals), communicable disease free, not unattractive (sight smell touch sound taste) and proficient in the communication (vocabulary, philosophy of language, english), psychology (incl. psychometric, assessment and classification of mental disorders, psychotherapy, memory and learning, performance psychology, positive psychology) and economics (incl. game theory, decision theory, health economics, behavioural economics).
Checkmate.
Speaking from personal experience, finding the right relationship can be HARD. I recently came across a rational take on finding relationship partners, much of which really resonated with my experiences:
http://waitbutwhy.com/2014/02/pick-life-partner.html
http://waitbutwhy.com/2014/02/pick-life-partner-part-2.html
(I'm still working my way through the Sequences, and lw has more than eight thousand articles with "relationship" in them. I'm not promising the linked articles include unique information)