I think too big of a gap may not be ideal. I'm only thinking about things like going through certain life stages together, at the same time. But, what you're comfortable with is what you're comfortable with and no reason to worry about it. When I was single, I only dated men my age or a little bit older than me (usually not more than 5 or 6 years). It wasn't so much intended as it just happened. I never dated anyone younger than me though. Ever. Until I met this one guy who was 5 years younger than myself. We've been married for 15 years! HA!