I don't think its a time thing-but a work thing.
What I mean is, that it takes conscious effort to work through those feelings.
One thing that I found helpful, is first accepting that our feelings don't dictate our actions. We can FEEL crappy about something we KNOW is good (like getting shots). There's nothing wrong with that.
What is wrong, is acting out on emotions that we are know are based in false information or are dysfunctional or abusive etc.
Second; is to REALLY visualize what was good/bad with any of the "I want" scenarios.
Third; force yourself to practice what you preach so to speak. In other words; if you want your partner to be accepting of your other love; YOU need to force yourself to behave more accepting of your other loves other love.
Also-it's been shown many times in empirical studies that if we DO an action (like treating someone lovingly) our emotions follow (it also has been shown that it doesn't as frequently follow that our actions will come after emotions).
SO-treat the other girlfriend with respect and honor her role and her position-which will help your feelings come into alignment with your actions and expectations. AND will show your current spouse that you are on board with DOING what you want him to do for you.
It does take time-like breaking a bad habit and making a new good habit. But it takes consistent, conscious, active steps in that time. If you just wait for it-it won't happen.
"Love As Thou Wilt"