Hi, I haven't seen your message, sorry for the late reply!
Yes it was intended, if she doesn't love you enough, there's no reason for you to stay exclusive.
There's a solution though, the simplier would be to ensure she stay in love with you.
On the newest version, if you have sex with a girl, it does increase the love (25% chance), and on the new "Harem Mode" you can set the love to stop decaying.
In the old release, it's in the cheat tab, "Stop Love Decaying"