this is a weird reply, but I think it was to be kinda troll-y. Really, do you think anyone doing tris at a level where they care about the training would end up in a situation like this?
I was dating a non athlete when I was training for my first marathon in 1999. He was inspired to run and started running too! and our first (and last!) christmas he gave me some awesome running gear. And last I heard, he still runs.
Sometimes I wish I was with a non athlete, but someone who wanted to cheer me on! selfish but true! instead, the guy I am with kinda competes with me, and I find this annoying at times...but its good to be with someone who gets it, though we have totally different styles...I am up and out the door by 5am and he dilly dallies around so we hardly ever ride together.
You might end up just by example inspiring her or him to get involved, just dont make it a requisite. And dont discount someone right away because of what they do or dont do. Believe it or not there is a BIG world out there besides getting up to bike 5 hours on a weekend. Knowing people with different interests is great, and ask someone out if interested dont over think it. Triathletes tend to overthink a lot of things way too much.