1) Do you want to be married to H and go forward with him or not? Spend some time thinking about this and decide on your timeline, there is no rush, and there is no right answer, only the answer that is right for you.
If you do decide to move forward with H, then you must accept him as he is, which means that whatever religion he chooses to follow has to be OK with you, you cannot control that. You can decide not to be with him if the religion is a dealbreaker, but it's not fair to H to expect him to change because of what you believe, and it's generally not a good idea to start a relationship with the expectation that you can change the other person or that they will change to suit your desires.
The only person you can change is yourself, and by changing yourself, you can change the dynamics of your relationship, but that is different than changing H. My guidance would be to ask yourself could you love H and be married to him even if he did NOT embrace your religion, or would that be a deal breaker for you?
2) You feel you are setting yourself up to be hurt again because your trust has been destroyed. Of course you can't trust him right now, he's proven himself untrustworthy and you haven't forgiven him. What I can tell you is that if you work together on your marriage, and ensure you're on a path where your mutual needs are being met, trust CAN be restored. As a matter of fact, your marriage can be stronger than it was before for having gone through this ordeal. You will be better educated and more aware of what it takes to make a marriage good than someone who never had to struggle, that's the gift you take from this. Read "The Five Love Languages" if you haven't already. If you can apply that book to your relationship, you can pretty much "affair proof" your marriage. Therefore, if you decide to go forward, you will need to have faith that you can forgive H eventually, and that you will be able to trust H eventually. You don't need to do those things now, but you have to have faith that it can happen.
3) Affairs are as old as marriage. The fact that your religion has a prescription for them is because it's been a constant problem throughout history. I listened to a great audio program, I believe by David Schnarch talking about marriage. He said that as humans, we are programmed to want to have many sexual partners, but we are also programmed to want to pair bond and enjoy emotional security. This is a natural tension that is part of who we are. He said that we all face a "two choice dilemma", we want the ability to engage in many exciting romances for ourselves, but we also want a spouse who will be faithful to us to deliver emotional security -- so we're tempted by the best of both worlds. When we get married, we're making a contract that says "I will forgo pursuing the romances I want in exchange for the emotional security of pair bonding". That's not to say that the desire for new romance goes away, just that we're agreeing not to pursue it.
Now as to whether "God led him down this path", that's something I wouldn't touch with a 10-foot pole
Accuray
Married 18, Together 20, Now Divorced M: 48, W: 50, D: 18, S: 16, D: 12 Bomb Dropped (EA, D): 7/13/11 Start Reconcile: 8/15/11 Bomb Dropped (EA, D): 5/1/2014 (Divorced) In a New Relationship: 3/2015
