@petedwayne1,
I agree with Jespah about counseling. I have the opposite experience, being very (and justifiably) angry with my parents.
My advice
1. You can't force a relationship on your kids. Right or wrong, they are adults and you have to accept what they want.
2. You can offer a relationship to your kids. Do whatever work in therapy you need to do. Listen to your kids needs. Then offer the relationsip you can.
If they need to work out the past with you, that may be part of it. But a relationship is something that happens in the present.
3. If they still don't want a relationship, tell them that you want a relationship when they are ready and that you will work to have a good relationship with them when they say that this is what they want. Then move on until they are ready.
You can offer, but you can't force.