DD, you can't prevent her from seeing OM by demanding that she come home directly from work and/or not go anywhere on weekends. first of all she will still find ways to do it; and the result of your demands will be just to make her feel "trapped" by marriage, while going out with OM is a fun fantasy with no responsibilities.
instead I suggest:
1) you can't demand that she come home directly from work every day, but it's reasonable to request that she be home by a reasonable hour. (maybe 7-8 pm, something like that. maybe in time to have dinner together as a family; or to be home when the two of you put the kids to bed after you've given them dinner, and then you and W have a quiet dinner together.)
and her time at home should be pleasant so she will want to do it more. similarly with weekend time.
2) also if you do things as a family, they should be fun things and not tiring. like suppose you and W take the kids to the zoo and after 1-2 hrs she is starting to get tired, that's a time to suggest going home (or to a fun restaurant) for lunch. if the kids don't want to leave, you can emphasize the fun-ness of the next activity, and suggest that you can re-visit the zoo again in a month or two.
3) the "date night" suggestion from earlier; try to have fun evenings together once a week or at least once every two weeks. the purpose is not to keep her away from OM (because if that is the only purpose then you've already lost) but because you're a fun guy to be with!
