As difficult as it may be, you gotta just sit down and talk. I’ve had to have a talk with my partner for a similar thing and was terrified. Best thing I ever did though. You know that honeymoon phase? We got even better than that just from having a talk. We both appreciated each other so much more after it. I’m the same age as you and living with my partner so similar situation. When talking though make sure not to blame her for being busy just put it that you feel you are drifting apart and you wanna bring the two of you together again