Chromie, Well here is my interpretation of the letdown O.
I think she is verrrrrrry embarrassed and creeped out by her own body and wants to eliminate any chances of that happening again, so she semi-invents the engorged story. By semi-inventing I mean that she no doubt was engorged by morning, but as a nursing mother I can tell you that letdown in the middle of the night happens ALL THE TIME. For a reason, for no reason, it doesn't really matter. Sometimes the way I was sleeping triggered it. And it does cause engorgement in the morning and a less-than-pleasant last couple hours of sleep.
But my point is that it is a fairly common occurrence for a nursing mom and she is somewhat handing you a line in citing it as a reason to forego orgasm.
My take is this: Do NOT take a 4 month hiatus. Why would you? How will this benefit your marriage? You are already mopy and sad at the thought of it, she will further entrench herself into "I am a lousy wife" land and things will continue to slide instead of slowly moving forward.
Your natural tendency is to avoid conflict. This is a situation that practically BEGS to be avoided, but fight against this and come up with a solution that works for both of you. She tolerates being engorged on those nights when letdown just happens--and she wakes at 2 a.m. with wet shirt and sheets--and she can do this for her sex life, too.
Now back to my original point: She is entirely embarrassed at what happened. I wouldn't try to 'talk' to her about it, just be the strong man you are and lead her through it. Don't make a big deal of it and try to soothe her, just lead her and she will gradually get over herself.
This is a womanly test, the kind that blackfoot speaks about, that involves many things: Does he think I'm gross?, Will he back off or insist on his own way?, How important is this issue to him anyway?...etc etc.
Reiterate to her that you are choosing a wonderful M.
You are not choosing sex over her comfort or any other way she might try to spin it. Someday I am confident that she will see that.