You can, but only after obtaining an annulment from the Catholic Church. You can ask your parish priest about how to get started. Most parishes will have someone assigned to that specific duty.
The process itself isn't too difficult. There is no financial cost to getting an annulment, but it does take a bit of time. (typically about a year total)
They ask a lot of in depth questions (essay style), and ask for you to provide the names and addresses of people who knew you and/or your previous spouse. The marriage tribunal will then review your answers and those of others to determine if there is reason to annul the marriage. Once that tribunal makes their decision, they will send it to a second one for another review.
Depending on how the last marriage ended, it may be hard to bring up those thoughts and feelings again.
If you have more questions, the website Q&A from my diocese is pretty helpful: http://www.chsl.com/AODOnline/Offices+an…
Currently going through the process.