He doesn't ask me to dance (anymore). Why?

This questions comes up in various forms all the time so I figured it's time to address it.

There are some guys who used to dance with you but they don't anymore. You don't know why. Where are some possible answers.

1) There are some guys asking you to dance at some events and not at others.
a) It's probably not about you, it about about them wanting to dance with other people more, maybe people who only go to those events.

2) There are some guys who used to dance with you but they stopped dancing with you at some point.
a) You may have offended them. You may have said "No" in a way that was more offending then you think.
b) If they were dancing with you when you were a beginner and now they don't anymore even though you are better, maybe there are some things you do or you don't do which bugs them too much. They tolerated that when you ere starting because they were hoping eventually you will correct it, but they probably lost hope or patience. Try to remember what they probably mentioned at practicas repeatedly, you are probably still doing or not doing that. If you suspect this is the reason, approach them at a practica and say something to the effect of "Listen, I need your help with something. I'm trying to identify what to work on next and I would like your opinion". Since you are not actually asking them to dance, it's a pretty safe way to go about it.
c) If they asked you a few times and then never again, the reason may be similar with the one in the paragraph above. Same suggestions too.
d) you may have slipped of their radar, very possible in a large community. Get back on their radar (see below).

3) There are some guys who NEVER asked me to dance
a) You may not be on their radar, very possible if the community is larger. Get on their radar. Ask a common friend to introduce you, make small talk when you can. Ask their opinion on something at a practica.
b) You may intimidate them. Same suggestions as above.
c) You may (appear to) have some dancing habits they can't stand. Same suggestions as for 2.b

Hope this helps.