An "unhappy relationship" refers to a romantic or interpersonal bond between two people that is not fulfilling or satisfying. It signifies a lack of happiness, contentment, or harmony between the individuals involved. Full definition
However, many people choose to stay in unhappy relationships due to comfort, safety, stability, or even fear of leaving. (powerofpositivity.com)
After being in a string of unhappy relationships with women from your own country, you have resolved to go for interracial relationships with foreign girls. (romancetours.eu)