Thank you for reaching out. 

It is permissible for married women to immerse for spiritual purposes. Halachically, you are considered a married woman until you receive your get, even after a civil divorce.

Once you have received your get, you should no longer go to mikveh even for spiritual purposes. Some communities do permit unmarried women to immerse in the mikveh prior to Yom Kippur, so you can use that opportunity if it is important to you. 

Please feel free to get back to us with any further questions. 

We wish you much hatzlacha and bracha going forward.