Maybe Gingrich told Boehner, “No thanks.”
Boehner isn’t exactly a shining beacon of effective conservative politics these days.
That could be, too.
OTOH, Gingrich has never shown any consistently good political sense about knowing who is and is not “good” to be seen with/supported by.
See Pelosi, Sharpton, Hillary, etc. That didn’t worry Newt in the least.
So it’s hard to make the case that Newt would be concerned that Boehner’s support would hurt him.