Thank you everyone for your replies, they were really helpful.
I will mention that I did go to a swinger's club with my husband once. It was a little overwhelming, but I didn't have a bad time. I'm glad I gave it a chance, and I am considering going back. I told my husband that he really needs to work at my slow pace, and he seems ok with that.
The idea to swing was my husband's idea as a way to "balance" things. He did not want to be empty handed while I saw someone else. I told him that saying that offended me to some extent, as if he was saying that having just me wasn't enough. And I told him that seeing other people had nothing to do with him not being enough. My relationships with other people are a separate thing (unless otherwise specified). I have the capacity to love more than one person, but it doesn't mean I love one person more than the other. But I do think my husband does have that fear that he isn't enough and that I have to look elsewhere to get what I want. I have told him time and time again that it is not the case, and I really try my best to comfort him that our relationship is fine and that I'm happy.
However he really has his heart on swinging, which I am fine with. I'm just worried if I will be able to swing with him. I did suggest that maybe he try to find a girl to have casual sex with on his own, but he doesn't sound very interested in doing that. I think he really wants me to be involved too. To some extent, it's flattering that he wants me to be around, but at the same time, I want to encourage that it WOULD be ok if he wanted to have sex with someone without me.
I guess another thing I should mention is that part of the reason why I am sexually shy is that I have not had many sexual partners as it is. I have had sex with my husband, and just recently my other partner. That is my sexual history.
I don't have a lot of sexual experience, and especially the last time I went to the swinger's club, people seemed really into it and comfortable with everything. I want to feel that brave, but it feels like a lot of pressure to perform for someone else, and I think that overwhelms me.
Anyways, I do realize this is a slow process, and that change won't just happen overnight. I am willing to be patient, and willing to learn what works and what doesn't. I think my main fear is that I won't be comfortable with swinging, and I am worried about the problems that will cause for me and my husband when I'm dating someone and my husband feels empty handed. I realize that is not my responsibility and I shouldn't feel bad about that, but I do want to be mindful of hubby's feelings too. I don't want to disregard what he wants, but I want to feel comfortable saying no, of course.
I plan to keep communications open, and try to keep checking in with how comfortable things are feeling. Thanks again for your replies!! I'll probably keep updating as things arise.
"When we are first born, all we know is how to want, we want food, we want attention. Natural instinct, I guess. But kindness is something that we all have to learn as we go. It's something that grows and develops slowly over time. True kindness isn't something we are born with, it's something we have to work at, we have to mold it and shape it within ourselves. Not everyone has it, but I think everyone has the potential." - Honda Tohru