This is all to be expected. These problems don't disappear. They have to be worked through, with each other or with other people. Time for real and complete transparency. Time for the phone call to his ex-GF.
Tell him:
1) He is never going to feel good or happy as long as he keeps feeling bad about himself for being such a sh*t. He CAN be a better man. WHEN he is, he will feel better.
2) Complete transparency required.
3) Public (so you have access) ending it with ex-GF completely required, making it crystal clear to her that he and you are back together.
4) He has to learn how to be monogomous again. This takes work. He has to put the work into it.
5) He straightens up or he is out. Period.
6) He needs to be honest and tell you about ALL the skeletons in the closet. NEITHER of you needs them haunting your present R.
And, FWIW, I'd say that, no, being content is not enough. A good life has joy, adventure, passion.
