Chris,
There are some mixed doubles schedules on here that might be interesting to you. There are
two here and some other
spouse avoiding ones here. If you try the search facility you might find a few more.
For the competition you have described, it is possible to arrange 5 rounds such that each player has 5 different partners and 10 different opponents. There will be some overlap, so there are 10 pairs of players who play together once as partners and once as opponets (e.g. M8 & M11)
(M02 F11 v M08 F09) (M03 F08 v M06 F04) (M04 F02 v M05 F12) (M09 F03 v M12 F10) (M10 F05 v M11 F06) (M01 F01 v M07 F07)
(M01 F08 v M11 F09) (M03 F04 v M10 F11) (M04 F01 v M12 F05) (M05 F07 v M09 F10) (M07 F03 v M08 F12) (M02 F02 v M06 F06)
(M01 F06 v M08 F04) (M02 F10 v M04 F11) (M06 F09 v M11 F07) (M07 F02 v M12 F08) (M09 F01 v M10 F12) (M03 F03 v M05 F05)
(M02 M03 v M07 M09) (M01 M04 v M06 M10) (M05 M08 v M11 M12) (F01 F03 v F06 F09) (F02 F04 v F05 F10) (F07 F08 v F11 F12)
(M05 M06 v M07 M10) (M04 M09 v M08 M11) (M01 M02 v M03 M12) (F01 F06 v F08 F10) (F02 F03 v F07 F11) (F04 F05 v F09 F12)
Will that work?