I've been S for almost 1 1/2 yrs and I've 'moved on' from W emotionally.
Did you give her the courtesy and respect of discussing your intention to resume dating? Did you two AGREE that during this phase you'd each be dating others?
Everyone draws this line in a slightly different place, Tar, but without the above I don't see how what you've done is any different than what you beat the cr*p out of your wife for doing. "It felt right, and I really don't consider us together anymore, so . . . " Right?