Hello! Guy here! Let's see, in my personal experience with my umm... one and only girlfriend! XD Umm, I tend to keep my eyes closed while kissing cause it's nice but occasionally I open my eyes for a second or two to see if hers are closed or how into it she is. They're not open for long and I REALLY LIKE knowing that she's into it and enjoying herself because when she enjoys herself I enjoy myself. So seeing her eyes closed for myself is pretty nice. I don't know if I'm alone on this because I sometimes feel like a pretty unique case when it comes to guys XP.
I usually close them the first few times because I know most girls check. Then afterward I'll close them most of the time because I know she likes that more, like I'm more into it. Sometimes I'll just take a peak and see what she looks like. People make the stupidest f*cking faces when they're kissing.