The first year is the hardest?!?! REALLY?!?!
The man won’t put her on his health insurance UNLESS SHE PAYS HIM FOR IT! That’s more than the first year being hard, that’s him being an ass and not caring about his wife’s health. What if she became seriously ill or was injured and needed to be hospitalized? Hospital bills add up fast, and she could be in thousands of dollars worth of debt after only a day or two. Would he then expect her to pay that off, too?
Not only is his family pressuring him to father his sister’s girlfriend’s child, (which would make him said child’s father AND uncle), it seems like he is actually considering it despite the fact that his WIFE is dead-set against it. First, it’s just creepy of them to ask, but especially since they are newlyweds with no children of their own, from the sound of it, (I would be especially pissed if my husband fathered a child with someone else before me after we were married). That’s more than first-year difficulties, that’s disrespecting his wife’s opinion and putting the opinions of his family first.
His mother borrows the car and he tells the OP that it’s none of her concern?! That isn’t post-wedding blues, that’s him being an arrogant jerk and excluding his wife from decision-making.
He watches her struggle with “her” bills (why won’t he combine finances with his WIFE, or at least help her out when she is having a hard time making ends meet?!) while he gives his mother money that his mom has no intention of repaying. That’s more than post-wedding difficulties, that’s him using money to control his wife and keep her in her place.
A counselor MIGHT be able to help with this, OP, but with his current attitude, I don’t see him agreeing to see one. It seems as if he doesn’t think there is a problem, or if there is, that the problem is with you. Granted, we don’t know his side, but from the facts you’ve given us, it seems like the only problem is him.
I would walk away and never look back, but that’s just me. I personally couldn’t remain married to someone with so little respect and regard for me and/or my opinions.