They are certainly living together as man and wife in 1891, although Rosa Mary is down as Floree Mary?!
Reference RG12/4619/37/20
4 Mount Pleasant, Wrexham
Beech, Thomas Head M 34 Corn Merchants Carter b St Martins, Shropshire
Beech, Floree Mary Wife F 33 b Wrexham
Beech, Elizabeth Ann Daughter F 12 Scholar b Wrexham
Beech, Albert Henry Son M 7 Scholar b Wrexham
Beech, Rosa Mary Daughter F 5 Scholar b Wrexham
Beech, Frederick James Son M 3 Scholar b Wrexham
Beech, Florance Emly Daughter F 1 b Wrexham
The family are also together in 1901, with an extra 5 children.
Reference RG13/5225/65/6
The 1911 census (not allowed to give details!) suggests a marriage c 1878, but I can't find it.
Possibly they didn't actually marry?
Also, Chester is only 8 or 9 miles from Wrexham, and in another country(!) so maybe they legitimised their partnership there?