Definitely alone. This is true of all video gaming, though. Gaming is my time, and I much prefer to keep other people out of it. Alone I have full control over my experiences. Even if my partner were to express an interest in participating, I would much, much rather keep those things separate; I'd be happy to participate if she wanted to play some of her games or read her VNs with me, or even specifically pick a VN to experience together as a dedicated activity if she was really interested, but for your average "oh this VN looks interesting, add that to the schedule" gaming? Nope. My time.