That would depend on how long you have known each other (if this is a date or a true boyfriend)
If this is a new date, then you may expect that he pays for dinner if he had invited you out. If the two of you just happened to go out and get a dinner, then it should be 50% or you could offer to pay the tip.
If this is someone you are dating for some time now, you would expect that he pays for the meal (withing the limits of his monetary ability) There may be times when you pay or split the bill. A man is not expected to always pay for the woman's needs/meals.
You could even offer to pay for coffee and dessert of for the drinks. It is only fair. If this is your husband, then the two of you would have a mutual understanding of who holds the money purse.