The Supreme Court of the United States declared back in 1967 that Virginia's "Racial Integrity Act of 1924," was unconstitutional, as a violation of the 14th Amendment's Equal Protection Clause. When this case, Loving vs. Virginia, was decided, seventeen states, had such anti-miscegenation laws. Mildred and Richard Loving had to fight for their relationship - had to fight for their love. The Supreme Court said they shouldn't have had to.
This is the most famous case based on race, but it certainly isn't the only one. There have been instances of discrimination based on ethnicity or religion too. The big one, which still continues in many places, is discrimination based on gender or on sexual orientation.
Love is love. It should not matter who is loving who. Of course the usual requirements for a contract should be in place - adults of sound mind, but race, religion, age, gender, sexual orientation, national origin, ethnicity, or financial status should not be part of the equation. If a man wants to marry another adult man, he should not have to fight for that right. The same of course is true if a woman wants to marry another adult woman.
It breaks my heart when I see couples fight for years and years only to keep being turned down. Thankfully much of the world has discovered equality. It's time for the rest of the world to follow!