Does a Big Dick Lead to Awkward Positions?

Hello,

I'm a straight male whose currently dating a really cool girl. I met her in college. She's cute and we get along well. But, recently I've been having some issues when we have sex. Every time I try to fuck her, she says it hurts too much. I tried using some lube to get things going, but she still feels uncomfortable. One time, midway through the sex she started clutching her stomach because it hurt so much. My dick's about 7 or 8 inches erect, and it's pretty girthy. She is pretty tight, but I don't have a hard penetrating her. I can't make my dick any smaller, so what sort of positions would help us have sex easier?

Ahhhh, the big dick paradox: Men wish to have a big penis, then suddenly when it's time to have sex, the girth becomes a disadvantage. The comment left below raises a good point. The best way to go for now is for you to be on top. This way, you're able to control how deep you go, and she's able to properly communicate with you. Another position would be for both of you to lay down sideways, facing each other. This also maximizes depth control for you and her.
I don't know if you talk dirty in the sack, but after about 10-15 minutes of you being on top, start pulling out some dirty talk. This is going to get her more excited, and maybe more adventurous.
If you're patient, this problem should go away after another couple of weeks. The sex won't be as painful for her, then before you know it she'll be going every which way. Just make sure you're patient: Don't make her feel like a prude just because she's tight. Make sure she understands that you're okay with this, and that it's a gradual process.