@i_lost_my_shoeee I think that would be a bad idea.
I know you feel bad about liking her, but distancing yourself would most likely hurt both of you in the process and she would probably be really confused especially if you don't tell her why.
I think it would be best to maybe talk to her? Set some boundaries, let her know you're not comfortable with her being all touchy like that while she has a boyfriend. It's she touchy like that with all her friends/her boyfriend or just you?
Either way, you should probably just let her know. It doesn't have to be a full-on love confession, just a little "hey, I'm a little uncomfortable when you do blah blah blah when you clearly have a bf" or wtv.
And I don't know if the whole thing with her being touchy is the full problem, but it does seem to be a lot of it (other than you having a crush on her which is not a problem AT ALL).
But distancing yourself from her, while it seems like a good idea now, will hurt both of you in the process and will probably make you feel worse about everything.
Sorry if this doesn't make a lot of sense (double sorry if you're not good with confronting people, but do NOT distance yourself from her)