Hi Undecided, it sounds like you & your husband are seeking two different things but using the same term. You seem to be talking & thinking about this as swinging-a couple enjoying the experiences together. Your husband sounds like he's actually talking about an open marriage-dating & enjoying others one on one, without the spouse present.
I am in an open marriage(we've been married almost 31yrs) and both my husband & I date & enjoy relationships with singles 1 on 1. In fact we have only been together to enjoy intimacy with others 3 or 4 times when we tried 3sums.
Both are very valid ways to live, it really depends on what you and your husband want, can emotionally deal with and where you see yourselves going with this.
Communication is the key, don't let yourself be pressured into doing something you don't feel comfortable doing!
Talk to him about what you want out of this and also voice your concerns. Find out by asking very direct questions what it is exactly that he wants and hopes to experience.
If you're worried he will force his side, write down your concerns, desires and hopes before you start the discussion-keep talking until you get answers for each point you have listed.
This site has some excellent,experienced, friendly members and even a dictionary to help you learn the terms for swinging. If you want to study up on open marriage, just type 'open marriage' into a search engine and start reading. There are also a number of yahoo groups focusing on open relationships.
Good Luck
Kathy