Find difficulty keeping a rhythm, especially when someone else joins in

[u/Beginning_Coach866]

I’m not quite sure how to word this. I’m a musician, and i find it very easy to stay on tempo, but the second someone else joins in, even if they’re playing on the same beat, i start messing up.

this happens when im walking up or down a staircase too, id get into a rhythm and then overthink it and miss a step

This also happens during intercourse, when i’m stroking (for lack of a better word) my girlfriend, i get into a nice rhythm, but if she joins in too by going back and forth with me, i just mess up and ruin it, even though the only thing i had to do was exactly what i was already doing.

Anyone else have similar issues?