In all genuine medieval Arthurian tales, Uther lay with Igraine disguised as Gorlois (or the Duke of Tintagel) and fathered Arthur at that time. Uther married her afterwards.
An account in which “she married uther pengdragon in love'' would appear to be a modern bowdlerized version.
A genuine medieval account is found at http://members.terracom.net/~dorothea/baladro/index.html which gives a full account of how Igraine met Arthur after he became king. Malory very much abridges this. In the original Igraine is again deceived, since Arthur, Ulfin, and Merlin already know that she is Arthur’s mother.
See also http://www.lib.rochester.edu/CAMELOT/geofhkb.htm for the earliest surviving account of the fathering of Arthur. Search for “Igerna”.
In Chrétien de Troyes’ “Perceval", Gawain discovers his grandmother Igraine along with his own mother and a sister of whom he had previously known nothing, in a magic castle called the Castle of Wonders. Igraine at least had long been thought to be dead. This account is not available on the web, but you can find the romances of Chrétien de Troyes in many libraries and almost any academic bookstore. See http://books.google.com/books?id=M7hEpibG4NoCn and http://books.google.com/books?id=7IdR47kTDkUC and http://books.google.com/books?id=yW-Dppu3rcwC.
The same story appears in the German romances “Parzival'' by Wolfram von Eschenbach and “Diu Krône” by Heinrich von dem Türlim”, although in these versions Igraine has a magician lover. According to Heinrich, Igraine became his lover after Uther’s death, but according to Wofram, she ran away with the magician during Uther’s lifetime and the young Prince Arthur went in search of her, but could not find her. See http://books.google.com/books?id=uh6au6yNUI8C and http://www.amazon.com/Crown-Tale-Gawein-Arthurs-Court/dp/0803244193/ref=sr_1_2?ie=UTF8&s=books&qid=1231004267&sr=1-2 .
The adventures of Gawain at the Castle of Wonders resemble those of Gawain at the Grail Castle in the “Prose Lancelot”. See http://www.thedcl.org/legends/europe/britian/westonjl/sgatgc/sgatgc.pdf beginning page 49. The Castle of Wonders is also the name of the Grail Castle in the Welsh “Peredur”. See http://www.lundyisleofavalon.co.uk/texts/welsh/peredur.htm .
And according to the “Livre d’Arthus”, Igraine was actually taken to dwell in the grail kingdom by Merlin. See http://www.archive.org/stream/arthurian07sommuoft, page 244. The text translates:
“... but as soon as King Pellinor knew that all of his fourteen sons were dead, he wished to no longer remain in his dwelling, but set out to sojourn in the Castle of Wonders along with King Arthur's mother whom Merlin had brought there; but no folk knew this except those who held the Holy Grail in their keeping.”
Apparently some tellers had tried to make Gawain’s adventures in the Castle of Wonders more closely connected to the Grail story.
I don’t know if you wish to use this tradition, but you should be aware of it if you are dealing with Igraine.
As to how to present this. You might be able to present different texts and point out the differences.