Sex drive is gone in 20s

My SO and I got together when I was 19 and I had a very very high sex drive. I am now 26 and can go weeks even months without sex and he feels like I am not attracted to him any more but I really am. I have to get myself in the mood just so I dont make him feel like I dont love him even though I do. Once we start its very good and I always want more, its just being in the mood to get started is the problem.

I asked my older friend who is in her 40s what she thinks and she said the same thing happened to her but when she was in her mid 30s her sex drive came back full swing. What are your thoughts?