yes, it looks like this IS about trust. this can seem odd since you are the one with a shiny new bf, as if he is the only one making a leap of faith and trust. but it involves you having faith and trust, too!
you have to have faith that he is honest with you, that he will bring up his concerns, that you two can work it out if that comes up, and to trust what he says, even if its too good to be true.
its natural to fear situations that seem "too good". you want to flinch almost like preparing for the blow of reality. you don't want to feel like a fool for believing and acting on a fantasy. this can keep you from fully investing, or at worst cause you to sabotage. its almost like walking through a paradise but thinking you are in an ambush. you can't enjoy the beauty around you when you are constantly looking over your shoulder for snipers.
he was brave to take a risk, and you can be brave, too. just knowing or saying you trust him wont make the feelings of wariness disappear overnight. there is nothing more your husband can say or do that will make those feelings disappear, either. but if you take others advice and pause before you question and look at it realistically then it will get easier. each time you take that risk and don't get burned, you will feel more confident. and maybe just looking at it as a matter of faith and trust will make it easier to resist questioning him.
all that's only true if he IS likely to bring up what bothers him. if he is NOT, then you must address that issue first.
that approach is what helped me, and i really hope it helps you.