This isn't about fault or blame. Funny how no-one is blaming the op for not being on the pill and relying entirely on her h to use condoms...? And if the dh wanted to keep the baby and the op wanted a termination no-one would be being supportive of what he wants?
At the end of the day what happened before is irrelevant, the op is pregnant and throwing around accusations of who should have used contraception and who is entitled to the ultimate say helps no-one.
Op the most important thing here is communication. Neither of your feelings are invalid, but you do need to come to an agreement over where the future lies with regard to this baby. You need to sit down and have a proper discussion over everything that is involved... so:
Your dh doesn't want any more children because you are currently financially secure, you're just getting your independence back, going from three to four is quite a jump, bigger car, bigger house, bigger outlay financially and the next eighteen years of your lives are pretty much sorted.... None of those reasons are invalid ones for not wanting any more children, and would be completely valid reasons for saying no if you had, for instance, wanted another baby and he'd offered those reasons as to why he didn't.
But you are already pregnant, and having already had three children you don't see yourself in a position to terminate a pregnancy, even though you see his reasons as being valid ones and actually would have agreed with him if you'd been at the talking about more children stage.
So, based on those factors you need to talk about whether:
- not wanting your lives to change is a good enough reason to terminate an existing pregnancy. It doesn't matter whether more children weren't in the future plans, as things now stand, another baby is in the future plans for eight months time. Given the relationship which exists between your dh and his children, does he really think that another child will be such a disaster that he is prepared to terminate it knowing the relationship he will most likely have with it once it is born?
- does he see not terminating this pregnancy as a deal-breaker for your relationship? i.e. if you don't terminate does he feel that he would then have no option but to leave? in which case the financial security and independence he talks about now would change anyway, as would his relationship with his existing children...
- if you continue this pregnancy, are you prepared to become a single parent to four children if this is a dealbreaker for your dh?
Similarly if you do terminate this pregnancy would it be because you absolutely believe that it is the right thing to do rather than because of your dh's wishes. If not, can you see your relationship lasting as a result? or alternatively are you prepared for the fact you could end up a single parent to three children because of the resentment this may cause?
Neither of you is in the wrong fwiw. Lots of people find themselves unexpectedly pregnant, and the reality is that if we took the "well they shouldn't have had sex if they weren't prepared to have a baby," line with every unplanned pregnancy then we would have no such thing as terminations or adoptions or even the need for contraception because people would only have sex to pro create, and we know that's not reality.
Talk to him. Lots of people react to an unplanned pregnancy in a "I don't want it," way and then come round once the reality hits home. Just because he wants you to have a termination now doesn't mean that this is the step you must take if that's not what you want. And it doesn't make him a bad person for wanting you to have a termination if he is usually a loving and supportive person - it makes him human.
But you need to talk, talk, talk as much as possible. If you usually have a good communicative relationship then there is no reason why you can't talk about this.
Good luck.