1. Your vagina probably isn't that deep. Most vaginas are about 4.75 inches, which is approximately the same size as the average penis, which means anything extra won't even be beneficial. If you've got an average-size vagina, a larger penis is just going to be like super-sizing your meal when you're not that hungry.
2. Most women don't orgasm from vaginal penetration alone. Only about 1 in 5 women can orgasm from vaginal penetration alone, which means his oral and digital skills are (statistically speaking) way more important.
3. It's less about size and more about proportion. On average, women tend to prefer a penis that looks proportionate to the guy it's attached to, so "too big" or "two small" might be less about the actual length and more about appearances.
4. If it's too big for you, it can easily be uncomfortable. Bigger isn't always better. If his penis is too big for your vagina, it can actually hurt or cause discomfort during sex. If your man is getting the job done, going any bigger won't necessarily help you any.
5. There's no direct correlation between size and satisfaction. Studies have shown that women don't always get more satisfaction out of a larger penis. Essentially, just because he has a bigger penis doesn't mean he's good at sex or knows how to use it well. There's no magic inches-to-orgasm exchange rate.
6. It's way easier to work around a small penis than it is to change other things about how he sexes. If he's a terrible kisser or bad at going down on you or a selfish lover, you're going to have a hard time changing those habits. But a small penis? You can just put a vibrating cock ring on him and everyone's happy.
7. There are positions that make a penis feel bigger. So maybe he pops out during vigorous doggy-style, but there are still positions that will make his penis size work for you.
8. Don't forget that porn isn't a great basis for what the average penis looks like. Unless you've seen a ton of penises, you're probably basing your idea of penis size on porn. Which is like basing your expectations of Asante Kotoko on Chelsea.
9. He's probably more ambitious in the bedroom because of it. Sex is great, but don't ignore a guy just because he's on the small side. He's probably fully aware that he's on the small side, and if he really cares about you, he'll find a way to please you in the bedroom.