Exactly. I actually found this to be a good version of this old, tired cliche story - I do understand and sympathize with Ben here, even though I think he made a mistake - but that doesn't mean the trope isn't in and of itself problematic.
To be honest, I think it's kind of OOC for Peter to advise Ben not to go through with his marriage out of fear. Because Peter's been there. Even though he'll always regret what happened to Gwen (and nice touch there, I much prefer that take to the Saint Gwen nonsense) he knows better than the other guys that you can move on and have a good, lasting relationship even if your girlfriend/wife/whatever dies on you. Out of all those men, I believe he's the only one who did in fact move on.
... hahahaha oh WAIT silly me that's right I keep forgetting the marriage didn't happen.