he's really confusing!

hi everyone.
i'm really confused about this guy i work with. we've been friends ever since we started working together and it was obvious to everyone around that we liked eachother. we always tease eachother and have loads of cuddles and at the end of every shift he drives me home.
we had a big chat a few weeks ago about this guy i was vaguely dating and had ended things with. he seemed pretty jealous and mentioned how i was really attractive and always dating someone yet the average guy like him never gets the girl.
Apart from that some flirty texts were sent but nothing really progressed beyond flirting.

However last night I was talking to another one of my co-workers and apparently he'd mentioned me. I think a bit of "go speak to her" / "go speak to him" went on and after he'd drove me home he finally kissed me.
He got really weird after that though. This guy is full on straight-edge and said he never did things out of the blue like this and he thought it would lead to sex and be awkward. He also mentioned that he doesn't "do" relationships.
Despite that some touching happened and he asked me to sleep with him. I said no out of respect for both of us and at this point I got really confused and said I was going home.

I don't understand what he wants from me. He's spent months flirting with me and telling everyone he likes me then when we finally kiss eachother he freaks out on me and acts like its a big deal. I also don't get why he was so keen on us sleeping together when he's clearly against being promiscuous.

I'd be grateful for any advice!