Do I have to deal with my ex spouse during the annulment process?

No. You do not have to have anything to do with him or her. All you have to do is let the Church know the present whereabouts of your ex spouse.

The Church requires that your former spouse is to be notified that the annulment process has begun so as to offer him/her the opportunity to make a response. So your ex-spouse will be sent a letter explaining that the process was initiated.

Your ex-spouse does not have to agree to the annulment, i.e. they can contest it. Or, he/she can also choose not to participate in the process - and it will still move forward.