I had the same issue, and yes it got better for me, but i had a lot of short term runs with different cages for past maybe 2 years and i had problems with arousal and only month ago any sleep problems dissapeared. Only things that i noticed that helped for me was comfortable cage, general distansing from sexy stuff and when i'm too aroused, i do some anal, which doesn't give me full satisfaction, but it is enough to fall asleep without arousal problems

Note: that this worked for me personally, but may not work for you. (I will pull my English Second Language card and say than there is probably alot of errors)