being more open

so my fiance has been bringing up swinger clubs and having sex there. he says it'll spice up our relationship. he's a sex craver and I don't as much. I'm very spontaneous. but couldn't do somewhere or all ages and females in front people and see me. is that something that happens with couples that have been together along time? they start wanting to be open with more? how should I react. cause so far I laugh and say no.