Actually its easy because the honest answer is both.
I wish to atone but I'm also seeking forgiveness (not been forthcoming to date). To an extent the two are linked - I'll know I've atoned when I've been forgiven if that makes sense.
Either way its selfish because my incentive is to try and purge my sense of guilt over this. (And other things)
Both mid 30s, 2 young kids BD 7sep14 XW moved on long ago, now living with OM1 D paperwork in progress