The OP has not identified whether they are the wife or husband posting.
I can imagine a wife posting, wondering what her decision should be. Even though she may be against swinging--as a couple, since she has no interest in it--she may be considering allowing her husband to swing alone.
I don't think it unreasonable that a loving wife who realizes that she doesn't have the interest in sex that she used to, may want her husband to still be fulfilled sexually and may be wondering if swinging is a solution.
Looking at this possibility, I would advise her to talk with her husband about how they arrived at this point in life. Maybe the differing sexual needs have always existed but only now are you discussing them. There could be physical, mental, or situational issues causing this change. Talk about all of these possibilities. Determine if a compromise can be reached that will satisfy you both.
I hope you register and let us know more about you and your spouse. We can only imagine what might be if we have so little to go on.
LM