Could you be with a guy who is okay with this opinion/belief?

I've been with my boyfriend for 3 months and he wasn't honest with me about how many kids he has. He told me he had 2 but I found out recently he has another son who is 20. He said he never told me about him because his son has cut off the whole family. I asked why and he said when his son was 14 he was sexually abused by a family member and that family members served time and got out in 4 years. Most of the family had decided he served his time and deserved forgiveness so they let him back into the family and my boyfriend admits he hangs out with him regularly and the person he told me it was had me disgusted. I asked why he would pick a rapist over his own son and he said he didn't. He chose forgiveness. His son did not and if his son wants to hold on to anger and cut off the whole family that's his choice. He believes everyone deserves a second chance and everyone deserves happiness. I can't agree with this and I'm not sure if our relationship can work with this difference of opinion. Now I don't have kids but if I did I can't imagine being friendly with someone who hurt them.