The being nice is actually further abuse. He is super nice because it debases you. It makes you question whether he really is the bad man, you start to think that maybe it was something you did or that you imagined it.
You are already realising that he is abusing you, that is the first and most important step.
Whilst you get your head around your next step i would advise doing some preparation. Getting legal documents like marriage certificate, mortgage, bank accounts etc copied. Post them to a friend or family member so that they can keep them safe.
get a bag of essentials packed up just in case things ever get bad and you do feel you just need to leave immediately. Leave it in the car or at a pals house.
If you are able to save some cash secretly as an emergency fund do so.
Do speak to womens aid. Even if you aren't ready to leave just now they will be able to help. They can arrange for an outreach worker to meet with you and support you whilst you are still at home. They can also help explain your options or work with you to organise leaving in a way that you will feel comfortable with.
A lot of women think that they will be wasting Womens Aid's time as their situation isn't "serious enough" I can assure you that that is never the case.
And last but not least, keep posting. There are (sadly) so many women on here who have been through what you are going through, and many more who are in the exact same position. You will be supported through this.