K.U.
I can understand how upset you must feel right now, but "confronting" her might not be the best approach. Your mother very well could have her reasons for not wanting him to be around you and could have been protecting you more than anything. You may have this image in your mind of who your father was, and this fantasy about meeting and reconciling and having the relationship that you never had. The reality is that your father walked out when you were 2 and never bothered to contact you since. Your mom stuck around and raised you and didn't leave when the going got tough. She may not have been perfect, but she was there, and he was not. That to me speaks volumes as to the nature of his character, as far as I am concerned.
My husband went through a very similar situation himself growing up and I don't know if we will ever know the full story, but I know that his father left him and his mother when he was around 2 years old also, never to be heard from again (and they were married, though they may have married because DH's mom found herself pregnant at 19 - and this was back in the late 60's). Supposedly it was because she got pregnant a second time and there were some doubts as to whose child it actually was. DH's mother went on to get married again and have 3 more kids (so 5 total with 2, maybe 3 different fathers). DH's father never called, or visited, or contact him in any way. DH kept thinking that at some point he would, but when he turned 18 and it still had not happened, he gave up, and decided he was not going to bother trying to find him himself anymore.
12 years ago, DH happened to get contacted by a woman who happened to be a half-sister by way of his father. They kept in touch for a little while but DH still was not interested in meeting his father. Then just last year this same half-sister ended up finding me on Facebook. She had been trying to track down DH (we had moved a number of times, most recently out of state, so that probably did not help) but while DH is not on Facebook, I am. We wrote back and forth some and she brought be up to speed as much as she knew. DH's father is alive. He is an alcoholic, and has fathered probably about 10 children with 5 different women, including a daughter before DH that he never wanted anything to do with, then DH, then 8 more after that with 3 other women. Only 1 of those women did he marry, and interestingly they've been married now almost 30 years (and she is not the mother of the half-sister who contacted me). Half-sister says almost all of them live in the same town but have very little contact with each other - she had not spoken or seen her father in almost a year, even though they live less than 20 minutes apart. She says he does not bother to contact any of them at any time. She did grow up with him some and has more of a relationship with him than DH ever did, but he's not really what one would call a great father since he can't be bothered to initiate any contact with any of them. He will talk to them if one of them calls him or comes over, but otherwise they would never see him or hear from him. He's just too caught up in drinking and can't seem to engage with those around him - emotionally he is completely cut off. Half-sister says that DH really did not miss out on much.
Sorry for the long rambling story, but point being is that your father may not have been this wonderful loving man that you might be imagining him to be. If he was really that great of a dad, he would have stayed more involved in your life. If you talk to your mom, I would approach from the standpoint that I would give her the benefit of the doubt, and consider that she might have been trying to protect you from someone that she thinks could have hurt you and would have caused you permanent harm. Ask her about him, and what he was like and what their marriage was like. For all you know, he could have had alcohol or drug problems, been a pedophile, or have been abusive in some way. Even if he wasn't, she still may have had her reasons, however unfounded, and may have just been doing what she thought was best at the time. No parent is perfect and nobody makes perfect decisions, but she still might have been doing the best that she knew how.