Quite right. I should not have said invalid. I should have said insubstantial, though obviously it's a big deal for you.
There are thousands and thousands of LGBT people who are married to a person of the opposite gender for excellent reasons like access to health insurance, ability to co-parent and adopt children in states where laws restrict non-heterosexuals, tax advantages, and avoidance of job and housing discrimination. It's truly a shame anyone would feel the need to live a closeted life, but as long as there are places in this country where being out can still get you killed there will be those who marry for safety as well.
Of course people with different sexual orientations and identifications can deeply love and care for each other, that's been going on as long as marriage has existed, but not everyone can adapt to living together in harmony under the same roof. I'm sorry you couldn't work it out.