Infidelity Support Group
Any relationship in which one partner engages willfully in sexual relations with another outside of the partnership is considered to have experienced infidelity. This breach of trust is often traumatizing for the faithful partner as well as the relationship, and support is often needed to heal emotionally and to decide whether or not the relationship should continue after...

It shows a person who simply never had the intention to be faithful and one who lacks character as well as an understanding of love.
From your short story it seems he never really committed to change or grew from his poor decisions. If the pain he had caused you in the past has not spurred him to commit to change then it is unlikely it will now.
Verify your suspicions and do not tolerate this behavior anymore.
If you are not having sex I am assuming that you haven’t tried to move forward. Or tried and haven’t had much success. What have you tried?
What makes you feel that he’s having another affair?
It's not personal that he doesn't love you but he simply doesn't have a capacity to love others more than himself.
He has relationships with people who benefit him and "loves" them in a selfish way.
Like others said this will likely continue unless he commits to lifelong change which will require intensive therapy.