Oh muma3 I am sorry, although maybe if some of the things I've said help you better understand why you're upset, it's kind of a good thing even though obviously my intention was not to make you cry!
I think you are right in the title of this thread: you do need to get a life. The question is, how is dp going to support you in doing that? How often is he going out? (I talked to my dh about this and he said "I don't get to go out on my own" to which I replied "because you are physically unable to leave the house, not because I stop you" "Oh yes"). You need to feel fulfilled as a human being, and being the mum to three gorgeous girls is great, but wanting to be more than that is quite natural and understandable.
If money is an issue, how is dp getting to go out without you on a regular basis? Don't sell me the "he earns it so he should spend it" story - I really hope that's not the case.
It may sound mad, but if you could get a job in the day that would break even after childcare costs, it might be well worth doing for your own self-esteem and sanity. What about a part-time thing a few hours each afternoon?
However, you still need to address why dp is content to go out on his own and not do things the two of you - can anyone come in to babysit one evening when the little ones are asleep? At least then you could go out for a meal or a drink together and be a couple. (Ironically, I have a babysitter lined up but dh is too ill to go out, so I might as well not bother!)