Decreased anal desire getting older

When I was younger I loved my girlfriend\wife using a dildo on me, I would be in heaven, felt so good I would even moan be so loud, I was always ready, and have urges for it and the dildo would slip right in no prep just lube. I would be so hard. Now days I still really like it, takes more prep, And I am not as turned on. Anyone else been through this,or know what I am talking about?