Why not look into the Open University?
You'd be able to take the 240 credits you gained in your first two years at university and do another 120 credits to top them up to a degree in your own time at your own pace. I don't know without checking the OU website whether or not you'd be able to top up to a degree in Childhood Studies or something similar, but you'd definitely be able to top up to a BA (Hons) Open - a degree that isn't in any one subject, something only the OU offers. You wouldn't have to start straight away, you could start in a year or two when your son is bigger (margery is wrong, if you drop out then want to go back you don't have to do the whole 3 years over - you have those 240 credits in the bank, as it were, and can request a transcipt from the uni to attest to this fact).
The one thing with switching to the OU is that you'd have to pay fees at the new higher rate (if you live in England, that is, if you live in Scotland or Wales you wouldn't) - as you started your course before the fee rise came into effect I guess at the minute you're paying fees at the old rate. But you would still be eligible for a student loan and financial support (as long as you study at least 60 credits a year. It'd be paid pro-rata i.e. if in a year you did half the amount of credits that a full-time student would do in that time you'd get half the amount of student loan. The OU also allow you to pay your fees in monthly installments if you don't receive financial support).
But I thoroughly recommend the OU - I've just done a postgrad course with them and they were way better than the campus-based university where I did my undergrad degree.
There is no point doing a degree without honours as people on here have said. Once you have 300 credits under your belt you really might as well push on and do those last 60 credits.
Like you, I have quit a lot of stuff in my life. For example, I dropped out of my first undergrad degree. When I went back to university and graduated it was an amazing feeling. I proved to myself and to other people that I can stick with things, something I'd needed to do and suspect you do too. So I think you need to enjoy spending time with your son whilst he's a baby - you're right, it soon goes and you should make the most of it - but also have a plan for how you're going to finish this degree.