Friends without borders

Similar to friends with benefits but brought to a more serious level. Two persons that have somewhat of a romantic relationship. There is emotion, respect, acceptance, attention, and sex but there is no restrictions on having other sexual partners or dating other people. Usually the persons in a friends without borders relationship give each other more attention and priority than anyone else if they are dating. There is no restrictions or rules on when to see each other, sex, or talk about the future together. Could be a romantic relationship where the parties are too scared to admit they love each other. There usually a connection that is amazing that they do not want to destroy by being exclusive.