manfred on Family Tree Circles

I have now been tracing my father's family for quite awhile now on ancestry.com and i have sort of come to a standstill with my father's family. Some things are not adding up so i thought i would give this site a go. I started of course with myself and then dad and grandad, i found grandad mann quite interesting, it seems he was in WW1 and was married twice his second wife being my paternal grandmother. But try as i might i cannot find any trace of this first wife. My aunt,dads sister, was in actual fact his step sister, so i am assuming that she is the product of this first marriage. I have actually got as far back as 1823 if i have tracked back correctly. I know some of my fathers family emigrated to new zealand, and possibly the USA. It also looks like that grandad's father and mother separated because on one of the census he is listed and she is not, on grandads miltary records it lists his mothers address in Bradford Yorkshire and list both his brother Walter and mother as next of kin, and fathers address unknown.