Right where do I start
Me and my Ex had been on and off for a year the first time he dumped me was in August he went to work away and came back and decided that was it, a couple of days later he rang and said he made a mistake and wants me back it he realized he really does love me.
The second time was due to me being paranoid about about other people ( he has never cheated on me) He used to tell me he loved me every day. When we split that time it was two weeks and olut of the blue he rang and said can I come for tea and I love you.
Things were fine with us but I knew he had a lot on his mind he has a daughter and really does not get on with her mum.He was sat in my house on the Sunday saying he had been doing a lot of thinking and how much he hated this ex (they have been over a good 15 years) she cheated on him a lot. He went home and text saying he loved me billions, it was the same on the Monday, then the Tuesday the texts were not as much not nor the Wednesday. He was supposed to come to my house on the Thursday night from work and text me in the morning telling me he loved me. 2 hours later he text saying it was over.
I was devastated he would not talk to me this time not answer my billions texts. We have been over this time for 4 weeks he then text saying about being friends I said yes (even though its hard) he was texting all day yesterday but even making rude comments. He asked me last night to be his guest at his works party which I was invited to before we split, I have agreed but just don't know what's going on in his head.

Things to know
He has never cheated I know this for certain
When we split he told a friend he loves me loads but we just can't be together
He has no real male friends
He hates his job
He is having problems with ex when we split
He knows I adore him
He still calls me by our pet names in text
Please help what do you make of it all

I'm wondering why you have brought up his ex if she has been his ex 15 years. You say he having problems with her, maybe they have been seeing each other. I don't know. Maybe he is in some kind of emotional crisis.
Give him space. Don't bug him, text him. But me, I would not take him back. This on and off stuff gets old and it's only been a year.

The reason I mention is Ex is because she has been a big pain in his butt for the past 15 years they have a daughter together and the only reason he has contact with her is because of that. He keeps things bottled up and know so part of his issue was his ex (by the way he was talking) I did think emotinal stuff he is a worrier and takes things to heart.
I am going to go to his work dinner and just see what happens he keeps saying in text as friends and to be honest think that is all we will ever be just so hard when I love him so much and he knows that

So are you going to be content hanging out as friends? I think you need to leave him alone and let him go to that party alone. He knows how you feel, it is selfish to ask you to go with him as a friend.

Move forward. Bright future welcomes you.

Moving on from this I went to his works function we had a good laugh but nothing else apart from he asked the DJ to play our song and mentioned a few happy times from the past he told me I looked fantastic but we both went home our separate ways. Then a couple of nights later he was texting me all night from a friends party telling me he was drunk, he then said he was on his way home and was passing mine (not on his route home). I let him in for coffee and he stayed the night yes we slept together the next day ge went home and that was that. Then yesterday he was twxting dirty stuff and I ended up going round and having sex with him. I should not have done it I know but part of me thinks if I did it he would want me back. I know he asks about me to friends and stalks my Facebook page. I just don't know what he wants and am to scared to ask as I love him too much but know just sex with him is wrong. He told a friend when we split he loved me but just could not be with me. I am thinking of texting him telling him I love him but can't be friends with him because of my feelings calling his bluff so to speak

Calling his bluff is childish. He does not want to be with you but has no problem being friends with benefits. Don't respond to his calls or texts, unless you don't mind being a booty call.