I think this might be it. 
DH has lied to me. Again. It was over a fairly trivial financial thing and to avoid an arguement/discussion about it, but I feel the trust is completely gone. He even said he didn't lie to me, he just didn't tell me... 
I feel his lying shows a lack of respect towards me. There's a huge history including him telling his family personal things about me/slagging me off to them/not standing up for me when his step mother treated me appallingly and in doing so she also threatened his relationship/contact with his son. I do still feel quite angry about all of this tbh.
I am struggling to think of anything good in our marriage except our beautiful daughter. He is not a loving or affectionate person (brought up that way) and I feel I have slowly given up. He's away now with work for a few months and won't be back in that time and I don't feel like I even miss him. Not really anyway. I feel like the only difference it makes is I can be more relaxed in my own home, do things in my own time and won't have any help with the DC.
I do feel like I still love him though. I want our marriage to work, especially for the sake of our DD and my DS's. I'm just not sure if I will be staying as I can't face the upheaval of moving and am scared of having to do things alone, as opposed to wanting to be with him any more.