When I first started dating my current gf, we had sex for 1.5 hours + every time but lately (currently at 10 months together) we can't have sex as often because of school and my stamina dropped a lot but I'm not sure if theres something specific to blame. sometimes its 5 min other times its the usual. I dont know what it is that is causing the drastic changes. She doesn't seem bothered by it in the slightest though which is good but I would like it to stay at the usual time. Sometimes I am not in the mood at all. Has anyone here ever gone through such dramatic changes so frequently before?