While growing up, early 90s I remember watching a science fiction anime on VHS tape, about a boy growing up onboard a spaceship with a robot.
The robot teaches the human child how to walk and run and play gymnastics, the robot was able to transform its arms to a handle bars-like shape and and let the human child play sports and practice.
The boy later meets a girl and no longer shows interest in the robot.
The robot gets jealous and very disappointed, and he tries to engage him in activities he is no longer interested in.
The unique style of animation makes me think that this was European or soviet, rather than American.
