You have only One Father, and although he found something else in that time frame of his life that he thought important enough to leave his family for, he is now and always will be your Father.
Remember something, it's hard to tell what's going on in anyones mind at any given time, the man might have thought he was doing everyone, including you a favor by not bringing his state of mind to your platter..
Nothing states Dignity,Composure,Discretion and Honor better than being a BIG enough person to offer forgiveness to those who have asked for it..I think your Dad is in that category...The Heart opens only one way there Horse Fly, from the inside out, you hold the only key
Give the man his dues, be big enough to accept the words and offer him a sit down.It may not have anything there for you, but you never know what it might have offered if your don't take the chance..
The man will have much to talk about, keep an open mind and just start off slowly, questions will be asked, just answer them. The conversation will happen if you allow it to without holding on to animosity..
Give It Up..Yo!
OH AND PS...I was 16 years old when I met my real mother for the first time, too many details to go on about..
You never know, until you try..