The 1851 census (HO 107/2461/372/54) has Jane Rees,Wesleyan Minister's(?) wife and family in Cowbridge,but no husband present.
From this clue the 1861 census has John Rees(Wesleyan Superintendent,mistranscribed!) and Jane in Cradock Street,Swansea.
The GRO gives mmn Rees to the children and indeed there looks like an 1842 marriage of John Rees to Jane Rees in St.Peter,Machynlleth.
Regards
Roger