Evolution of close binaries often proceeds through the common envelope stage. The physics of the envelope ejection (CEE) is not yet understood, and several mechanisms were suggested to be involved. These could give rise to different time-scales for the CEE mass-loss. In order to probe the CEE-time-scales we study wide companions to post-CE binaries. Faster mass-loss time-scales give rise to higher disruption rates of wide binaries and result in larger average separations. We make use of data from Gaia DR2 to search for ultrawide companions (projected separations 10^3^-2x10^5^au and M_2_>0.4M_{sun}_) to several types of post-CEE systems, including sdBs, white dwarf post-common binaries, and cataclysmic variables. We find a (wide-orbit) multiplicity fraction of 1.4+/-0.2 per cent for sdBs to be compared with a multiplicity fraction of 5.0+/-0.2 per cent for late-B/A/F stars which are possible sdB progenitors. The distribution of projected separations of ultrawide pairs to main sequence stars and sdBs differs significantly and is compatible with prompt mass-loss (upper limit on common envelope ejection time-scales of 10^2^yr). The smaller statistics of ultrawide companions to cataclysmic variables and post-CEE binaries provide weaker constraints. Nevertheless, the survival rate of ultrawide pairs to the cataclysmic variables suggest much longer, ~10^4^yr time-scales for the CEE in these systems, possibly suggesting non-dynamical CEE in this regime.

Cone search capability for table J/MNRAS/494/1448/table2 (Resolved binaries found in the MSWD sample)

Cone search capability for table J/MNRAS/494/1448/table3 (Wide binaries found in the MSWD sample)

Cone search capability for table J/MNRAS/494/1448/table4 (The identified sdB systems with wide companions)

Cone search capability for table J/MNRAS/494/1448/table5 (Wide binaries found in the CVs sample)