Sophie credits fiancé Dillon with being supportive and keen to learn about the condition.
"I had plenty of hours of education from Sophie over a G&T, because Sophie was so open about it," he said.
"It made learning a lot easier, but she didn't mind the stupid questions as well."
The Newport-based Dragons prop, 29, who has 57 caps for Wales, said asking questions and being open was key to offering a partner support.
"Just try to help in whichever way, like I always say 'is there anything I can do' with the answer 99% of the time being no but at least I like to ask... and get a hot water bottle every now and again," he added.
Sophie, now a women's health advocate and podcaster, said that being with someone supportive, whatever the challenges, was vital.
"I genuinely don't think I could be with someone who didn't want to understand the endometriosis, because ultimately, I will live with it forever. It's chronic," she added.
She wants more women to feel confident talking about the impact endometriosis can have on sex and intimacy, although acknowledged how daunting it can be.
"Now I'm an open book... six years ago, I couldn't even say the words periods without flushing red," she said.