Jason hates himself. He stepped away from his son when he has wanted to be a father for so long. How little would you have to think of yourself to be able to do that?  Of course he has dreams, and his dream would be to be with Liz and the boys. He doesn't think he deserves it though. Everyone always complains that what he is doing doesn't make sense. Jason has explained it himself. When Franco asked why he does what he does Jason told him because it was what he could do, the thing he did well. He has stated that many times over the years. I think from his characters point of view he sees himself trying to do anything else and failing. He thinks he is a loser. He is afraid yes, a coward.

Sam accepts what he does and supports him. What that also means though is that unlike Elizabeth, Sam doesn't think more highly of Jason than Jason himself does. That is why Franco knows Jason made the wrong decision. Since Sam loves Jason because of who she (and Jason) sees him to be, a killer, she is the last person who he should save in any situation. She should be expecting things like that to happen.  All Sam's supporting of Jason when he feels down about who he is and his actions show is that she and Jason are not on the same page.   He hates himself for who he is and she loves him for it.

When you feel down and pissed at Guza think, would you rather have your fave couple be together because one half thinks they can't do any better, or apart because they think they are not worthy?

I believe a lot of anvils are dropped that we may miss due to negativity.