Exploring your body or letting your partner explore lets you know what you like and what you do not like. It helps them and you know what turns you on and what does not.
It's okay if you lose interest it just means you need to find something that interests you. Try something different use and do things you would never use or do. Try wearing outfits, dirty talking, try using toys.
Try different positions just do something that will bring back interest and spice things up in the bedroom. Just enjoy and have fun!