It is not uncommon for partners who have been together for one or both to want to spend time with friends or doing things that interests him. After a while, the relationship becomes more steady and the need to constantly do things together or be together wears off. That is normal. It is healthy to be autonomous in any relationship. Otherwise the people become enmeshed and that is not healthy.
Only you know what kind of a relationship and attention level you would want to get from him. If you are truly unhappy, then go after what you believe will make you happier.