Hi Jac1234,
Congratulations on successfully working all the way up to the largest dilators.
For some women the largest size dilator does always give some slight burning or discomfort. As long as your partner is slightly smaller than the larges size dilator, I would say it is ok to try intercourse.
I would dilate with the largest size prior to intercourse.
I find that some dilators are not completely pain free until you can insert a dilator bigger than it. So unless you continue to work up to further bigger sizes, that last dilator size could still be a little problematic.
The glass dilators from crystal delights do have bigger sizes, and the size 7 and 8 can be really helpful when you have a large partner.
Hope this helps,
Melissa