By loving him as a friend and father, do you mean that you're no longer wanting a sexual relationship with him?
Personally, the struggle here would often seem to be trust. It is hard enough to trust the first time, that regaining it presents a real challenge. Do you trust him with your vulnerabilities?
In most of my experience, aside from some magical disney chemicals which fade quickly, most of love is an action rather than a feeling. Waiting for it to come around will probably not work. If this is a person you value enough to want to get that connection back with, for whatever your own reasons, it will take you deciding to take leaps of faith with yourself and your vulnerabilities, and trust that he will be there to catch on the other side of the rift. You have to choose to trust again with your body and your heart and your fears, even though he probably doesn't deserve it, if you want to get back to that sort of feeling and relationship with him.
I am not, btw, saying you should, necessarily, just that I don't believe that you can get back to sexual closeness through talking in therapy. At some point, if that is the goal, you need to trust him with that intimacy to build intimacy with him again.
Personally I would have a very hard time, but then I structure my relationships as open relationships where the one rule is that you do not lie to me, which "cheating" is really a form of, since they're allowed to have sex outside our relationship as long as they're honest about it. So for me, getting past having been lied to would be unlikely to happen. But if for some reason I was trying to do so, and build intimacy again, I understand it to be something that takes action at least as much as words. It takes deliberate trust again, even when that's scary and they haven't proven trustworthy in the past.
I don't know your feelings about monogamy, but it is possible that considering poly for both of you would be one path toward less pain. For some it might just be more painful. So it depends on you, but if you want that closeness with him, you may have to decide to create it even though you have reason to doubt his success as monogamy in the future.
You have to decide what you value most. Him, a sexual relationship with him, trusting him, etc. There are many outside the box answers, but all of them take action on your part if you want it to change.