well if you have never had sex before then yes, you just need to give it time. You should be happy that he isnt all into having sex because that is usually a sign that he isnt serious.
But if you have had sex in the past and arent lately you should talk to him. Maybe he just wants you to spice things up a little, or change it about. That or he might be not that much into you anymore(sorry)
either way, you can be serious without sex, but it depends on what the circumstances are.
good luck