Open-marriage advice?UPDATE

so me and my husband are married and we've been together for 5 years we got married when I was 18 and he was 20. we have only ever been with each other all through High School and a few months ago I had brought up that I wanted to sleep with other people because I was feeling unsatisfied and like there has to be more you know. I never seriously brought it up I just mentioned it and that was that. Today my husband comes up to me and says that there is a girl that he finds attractive and wanted to know if I was still considering an open marriage. it really threw me for a loop. Because I love my husband and I know he loves me and he said he would want to set up terms that we're both comfortable with but I just can't get over a fear that he won't want to have sex with me anymore or that I won't be attractive enough to him. and I want to go and do the same thing but hear it coming from him bothers me. I just really don't know how to approach this. Plus we have a kid. Any advice? UPDATE i went ahead with it and at first it was uncomfortable and there were some issues, but now its actually amazing. we r so mucj more open and i feel like a weight was lifted off me. this def isnt permanent but its fun for now