firstly, your dp sounds extremely controlling, although it also sounds as if he is in some way intimidated by this group of friends he associates with. How did they all become friends and how do the other wives feel about this? chances are you're not alone.
Secondly, there's never such a thing as not being able to leave. If the house is in joint name then you will certainly be entitled to a steak in it should you wish to leave, possibly even the deposit you put in plus half the equity, considering you're not marriage and so the law is slightly different with regards to partners who cohabit.
Have you tried talking to your dp, does he know how you feel about this, and if so what does he say? Also, if he changed his ways, i.e. started going out with you, giving you more freedom etc and stopped controlling who you and your children are allowed to be friends with, would you want to make things work with him? if so, you should have a serious chat about how you feel about everything, but if not, you should start to look at your options, do you really want to live like this for the next 20, 30, 40 years? If your partner controls who you are friends with, how will he be when your daughter grows up and wants to start having boyfriends? will she be allowed to date guys who are not from within the inner circle?
Only you can make the ultimate decision, but you have to do what is best for you, and it shouldn't have to revolve around money, it won't be easy, but if the alternative isn't something you want to do any more, then you can make it work.
good luck x