There is someone looking for someone just like you, so don't just hang back. There are a number of reasons people enjoy swinging: having an exciting experience with someone you think is hot, watching your spouse as if he/she is a porn star, knowing that your spouse is enjoying him/herself, giving pleasure to a sex partner, and a forgotten on - appreciating and showing appreciation for a sex partner's characteristics that are not usually appreciated.
For example, in our group there is one woman who has an unusually loose pussy and she knows it, but I love it, especially when she is sloppy. It is extremely difficult for me to cum with her, but when I do it is the most intense orgasm ever for me. She can tell how much I like it, I compliment her for the great orgasms, and she is flattered. In our group there is a guy with a bent dick who one woman seeks out because in the proper position he really hits her spot. Another young wife has saggy breasts with her nipples pointing downwards. Two of the other guys think that they are beautiful and she is the sexiest woman around. They particularly like for her to assume various poses, particularly on all fours, and see how her tits fall. Another woman has a post-baby belly paunch which one guy is crazy about. One of the wives likes the way I can extend an intercourse session, sometimes stopping moving altogether for a while, then pretty much cum on command when she is ready.
So just a way to say whatever you think is a deficiency in yourself is something that will be prized by another sex partner. So perhaps as a couple you should put yourself out that way, as you up front with all of your characteristics, and include plenty of pictures. Describe your husband more briefly and include just one fully clothed picture of him. That way you'll know that the responding couple, maybe both him and her, are already interested in you. Keep us updated on your adventures.