dyspurnia; pain during intercourse" is also another problem you may have... I suggest seeing your doctor and talking to them about possible problems, You can have this taken care of. It is not abnormal for this to happen.
Have you gone to the Doctor to make sure its no infection from inside or irritaiton around your vagina. i have the same problem at times and haven't been able to have comfortable sex, and in my case its because of the iud that i have.
Since you say: "after about inserting three times after short breaks, the pain reduces considerably", I wonder if it has something to do with size issues? That is, are either you built small in the vaginal area and/or is he built big in the penis area? If the pain did not stop at all during intercourse, then the problem would be even worse, but at least you have found some way to curtail the pain quite a bit it seems. Do you have sufficient foreplay before he enters you, so that you are naturally lubricated and relaxed enough before penetration instead of just jumping into the action? Foreplay is a major part of sex that many couples tend to overlook, especially from the male side.