I think both monogamy and polygyny have their own biases. The reason you want to have multiple sexual partners is because humans are selfish by nature, therefore staying monogamous can be a good practice for practicing selflessness. It also depends on the type of love between you and your partner, do you think you both really fell in love with each other? If you did, you wouldn't have the need to have other partners because you would knew that'll hurt your relationship dynamics and no other women, no matter how hot they might seem, complete you as your girlfriend does, both spiritually and physically.
So, even if you really think having sex with other people is a way of you to "spread the love of God", you shouldn't do it without the consent of your partner. If you think she also has the right to have sex with other men in order to spread love, you should discuss it with her.