Vaginal tears

I'm in a long distance relationship so I of course don't have sex a lot. We see each other maybe once or twice a month for a few days and almost every day we have sex. I'm a really small woman and he's pretty blessed but unfortunately, I usually tear right at the opening of the vag close to the skin separating the anus. I don't think lubercation is an issue cause I don't have any problems getting wet. Sometimes we have to stop cause it just hurts too bad. Anybody know how to prevent tearing??