Just starting down this road (officially) myself so its valuable info to have.....
Here is what I would lean towards should I ever post an ad.... (not necessarily worded like this... just throwing out ideas of what we are looking for so you get the idea.)
Mono wife/nonsexual poly husband in search of....
someone who likes the outdoors, is health conscious, generous with feelings and affection. Wife likes to garden, take care of her chickens, go to church, sing, listen to music, dance. Husband likes fishing, reading, hunting, (although its mostly just hunting with cameras), horror movies.
Both like nature walks, sushi, eating out in general, campfires, camping, documentaries.
THis just scratches the surface really.... male or female doesn't really matter, but we both relate better to females, A couple that we could connect with with out worry about who is going on a date with whom would be great. We are both pretty affectionate, and open with our feelings. Some contact including hugs, pecks, hand holding, snuggling while watching tv or movies..... Just someone to share lifes journey with in general that will "be there" both physically and emotionally. We are great with eachother, but have varied and different interests that don't always mesh well.... so we look for friends to do these things with rather than drag the other along. The hope is that the relationship goes beyond the typical superficial "drinking buddy".