Guy married Joan de Carew in 1330 in Pembrokeshire, Wales. Joan was born in 1320 in Carew Castle, Pembrokeshire, Wales; died on 12 Apr 1348 in Walwyns Castle, Haverford, Pembrokeshire, Wales. [Group Sheet] [Family Chart]

1. Jane Brienne was born in 1337 in Holway, Taunton, Devon, England.
2. Elizabeth de Brienne was born in 1338 in Laugharne, Carmarthenshire, Wales; died in 1394 in Okeford Fitzpaine, Dorset, England.
3. Margaret de Brienne was born in 1340 in Walwyn's Castle, Haverfordwest, Pembrokeshire, Wales; died in 1362 in Beckingham, Somerset, England.

Guy married Elizabeth Montagu (maid. name 1) on 10 Jul 1350. Elizabeth (daughter of Sir William ( 3rd Baron Montacute, 1st Earl of Salisbury, and King of Mann) De Montagu and Katherine DeGrandison (maid. name 1)) was born in 1327 in Donyatt, Somerset, England; died on 31 May 1359 in Ashley, Hampshire, England; was buried in Tewkesbury, Tewkesbury Borough, Gloucestershire, England. [Group Sheet] [Family Chart]

1. Guy IX de Brienne (maid. name of Laugharne) was born in 1350 in Laugharne, Carmarthenshire, Wales; died in 1386 in Walwyns Castle, Pembrokeshire, Wales.
2. Phillipe de Brienne was born about 1355 in Walwyn's Castle, Haverfordwest, Pembrokeshire, Wales; died after 20 Oct 1406.
3. William de Brienne (maid. name of Kemsing & Seale, Sir) was born in 1359 in Walwyn Castle, Haverfordwest, Pembrokeshire, Wales; died on 23 Sep 1395 in Killed In Combat (Dsp).