I think its more of a guilt thing with hubby. Trying to make up for missed time while they were growing up. Im his 3rd marriage. It just gets irritating.
Holy crap...no no no. So does your hubby give in to them? I understand the whole daddy position and they are probably use to getting everything they want. He needs to learn to say no to them especially with the new baby coming!! My mom's side of the family expects everything from my grandpa. He just adopted a child and all his children still expect all thier allowance every week even though they are grown!!
They seem selfish. I can see asking for help with a bill but show some gratitude and at least attempt to pay the money back. Talk to your husband about it.