OK, so you don't want to move on. If you did, there are options is finding alternatives to finding a reconciliation to your miscarriages, alternatives in traveling to the same place without any physical contact and realign your thoughts so you don't constantly thing that you're ‘stuck in any situation'.
You're still very much emotionally attached to him as he is you. He's caught in the middle of a situation where his feelings are being pulled in two directions. I'm guessing the cuddling isn't just a one-off experience either – check out a recent post When Is It Cheating which you might find interesting. Just because there's a lack of sexual activity doesn't mean you're not in a adulterous relationship.
So, it will now be a matter of your ex having to eventually make a decision and a choice on either you and his current girlfriend. It's really that simple.