I've seen this said a lot of different ways. I've heard that straight relationships are more based in love than gay ones. I've heard that monogamous relationships are more true to love or sensible than poly ones. I've heard polyamorous relationships held up as more sensible and loving. That mentally disabled people's relationships are not as full.
All of this is wrong. All of these have the capacity to be wonderful, glorious. Or to be hurtful.
All intimate relationships have the same standards - The consent of the participants. The respect and compassion with which they treat eachother. Whether the relationship enriches both of them. Whether it leads to healing, growing, blossoming. Whether the relationship enriches the community around them.
The outward forms of these things may look vastly different. They should look different. Shaped by the people in them. But they're not some weird exotic thing. They have the same heart.