I really need some help on this issue. I am very hurt and scared for my relationship because of my boyfriends mother. Here is the story...

My boyfriend and I have been together for almost 2 years now and we love eachother very much! We have had a lot of great times and some hard times, as does any relationship. My BF is 24 and I am 21. He works and goes to school at a University and lives in his mothers house so that he can afford to get through school. I live about 45 min. away in a larger city and also work and go to school and live on my own. We see eachother about 3 times a week, and our relationship is good.

Well about 4 months ago I was spending the weekend at his house, or his mothers house rather. We were rearanging his room for some new furniture when we suddenly got into an argument that led to him snapping and saying something that GREATLY offended me and my beliefs and in my anger I threw a picture frame accross the bed and got up to leave, but as the picture frame flew through the air, my BF was getting up and it hit him in the face instead of falling on the bed!!
I am the only one who really knows that it was an accident. I am not the kind of girl who would intentionally, physically hurt someone, but I do NOT justify my actions.

Well this caused a huge scene and his mother was there and yelled at me, and my BF proceded to take me home. We drove the 45 min and barely spoke. We had a mini break up for about a week and then he came to see me and we completely talked about it and embraced eachother and forgave. The following week I made phone calls to all his family members to apologize for my mistake. When I spoke with his mom she started out by saying that this is something I need to deal with my BF not her. But she also said she didn't want me to come to their house again unless I apologized to her, which I did apologize and let her know that I do not justify my actions and we spoke in detail about this, but in the end I was forgiven by my boyfriend and his family!

Now keep in mind this was 4 months ago and everyone accepted my apologies and we have had many good times after that event.

Now this week my BF invited me to go on a weekend trip with he and his family and some friends to attend his grandfather's 85th surprise b-day party and to also celebrate his mother's b-day at a hockey game. I was excited to see all of his family again and to bond with everyone and just have a good time with everyone. I got that Friday off of work, packed and drove to my BF's house Thursday night. Well, as I arrive my BF sits me down and says that he has some bad news. He tells me that the bad news is that his mother just decided that she does not want me to go to the family event because of the mistake I had made 4 months ago and that she is still very upset about it. We decided that we would talk to his mother about it. When I talked to her, she told me that she does not think that I am good for her son anymore and she doesn't like fights in her house and she doesn't like "drama" and that she is mad that her son and I got back together after our big argument. She said that she is so mad about it that she is almost to the point where she doesn't want me to come to her house anymore.She also said that I may have apologized, but it will never go away! Isn't that called "Holding a Grudge?" She said, "For every mistake in life there is a punishment and your punishment is that you cannot come and be a part of our family on my Father's birthday!" I was speechless and hurt and tears filled my eyes. I asked if I could still attend the hockey game, as there would be friends there, not just family. His mother said that she did not want me to celebrate her birthday with them and that she doesn't want me to go. My BF was upset with her and tried talking to her but her mind was set. I am not mad at my boyfriend for deciding to go because I did not want him to miss out on this family event because of me.
He and I talked about the incident of 4 months ago and he explained that he had forgiven me MONTHS ago and that he loves me. He explained to me that if he didn't love me and things weren't working out, then we wouldn't be together.
But the problem now is that since his mom said all these things to us, I feel like our relationship is rocky... we did nothing to make it this way, his mother did.

The worst part of all was watching all of them leave! His mother was waiting in the car as his sister and her boyfriend got in and my boyfriend said good bye to me and I watched them drive away to spend a fun weekend together!

I AM SO HURT BEYOND BELIEF! Someone please give me some advice! I have apologized many times to her, my BF has forgiven me and that is what is important, but I don't want her to use my mistake against me for the rest of my life! I love my boyfriend very much and I am not about to let his mom ruin a good thing!