It seems to me that this situation is actually very very simple. I've had my "road to Damascus" moment, but others seem to be struggling with it, so let me explain where I am coming from.
1. We had a referendum which I am sure everyone will agree, despite all our preferences, reservations, objections or what-have-you's, was positioned as a, once-in-life-time binary vote on whether we should stay in, or Leave. And also there was a universal commitment from all involved that the result would be respected.
2. Realising what a cluster-fuck this was, I chose to ignore this and argued passionately for a full reversal or a second referendum in order to get the result I'd have preferred. In hindsight, this was wrong. The result must be honoured. For two reasons, (a) because to not do so, would destroy all faith in democracy in this country and (b) because those who voted Leave will never let it drop anyway. We cannot move on, and start addressing all the problems in society - the very things that many people were driven to vote Leave over - until we move on and Leave.
3. There can no justification for rejecting a democratic referendum result. However, if there was to be one, then the only plausible objection might be that no-one voted to leave without a deal. That people were told there would be a deal. That the economy will be trashed without a deal. We now have a deal, so that objection is eiiminated and can no longer be valid.
Therefore the ONLY sensible option, the only morally acceptable option, is now for MPs to vote to accept the deal. I think enough of them will realise this and it will be passed.