You have been with him for a while. If this is something bothering him just point out to him your concern. You do have a right to voice it.
Of course, at the beginning it is only a concern (and not a fear or stress wrecking occurrence), since he had not done anything as far as you know to break your trust.
If you seem too clingy or suspicious he may get frustrated. So, just calmly ask him how he would feel if the roles were reserved. If he says he trusts you and knows you'd do the right thing, then give him the same option. Until you see something more serious coming out of this whole thing, just treat it for what it is for now- a business venture.