Need advise on relationship please

I'm a 18 yr old and I'm in a relationship with this really cool guy and he says he loves me but I don't see an entire future with him. I broke up with him for a week and I missed him so much and he missed me. After he called me to ask if I was OK . I told him how bad I feel that I broke up with him because I do still really REALLY like him. We got back together and everything is OK between us. But. I still don't see us spending our whole lives together. Am I lying every time I say "I love you" to him?