Dissatisfied [23F] in relationship with [24M]

My boyfriend and I have been together for over a year, sharing a home, playing on the same sports teams, and maintaining a close circle of friends. Despite this, I've been feeling increasingly unhappy lately, and I can't pinpoint the cause. I'm wondering if it could be seasonal depression or if I've outgrown our relationship. He's very focused on his own ambitions and has skipped significant life events in favor of pursuing his interests. I've taken on the role of his supporter, but I'm beginning to feel exhausted by it. While he’s a great guy, I’m uncertain about how to address this feeling or if it’s simply a seasonal phase. Has anyone else gone through something similar? I'm torn between whether it’s time to move on or if it's just the winter blues affecting me.