Surely it's worth broaching the subject with him? If this is important to you, I agree with the previous comments that you need to have faith in your relationship and open up with him. See what he says. You'll never know if you don't raise the idea.
Why not try easing your husband into it over a period of time? Perhaps start with finding a couple that would like to play with you both (and make sure the woman will appeal to him). If he can be in the room with you at the time (and enjoying some fun company of his own), perhaps he can get used to the idea of you being with another man. Then, when he's comfortable, you can progress to seeing a man on your own, and perhaps later with dating.
My husband and I are on this journey at the moment. I wanted an open relationship but he wasn't comfortable with the idea of me with another man. First of all I just asked him to read about it and learn more (The Ethical Slut, & Dan Savage). Later, we went to a swingers club and I found a lovely lady for us to play with. Then, we found a couple that wanted to play with us both, and have been developing a relationship with them over time. He's now said he's comfortable with me seeing a man on my own.
My husband loves me and genuinely wants me to have everything I want. It just takes time for him to get used to it and feel comfortable, so I've been giving him that and moving slowly. We've had some great learning experiences along the way - mostly when he got upset about something, we talked about it, and we learned more about ourselves and our relationship. Overall he agrees with me that the whole journey has been immensely worthwhile, strengthening our relationship.
If you love and trust your husband, I'd suggest you go for it, but be gentle with him
It sounds like you have the patience and love to make this work