What if you love someone but are polygamous at heart?

my partner is amazing, sweet not materialistic smart, attractive...the whole shabang , but i have this nasty procreate gene that I've tried to deprive and ignore. When the relationship first started I just bottled it away and deprived myself and "faked" that I want to be monogamous like most people in society but I just cannot rewire my natural instincts it is bad enough that soon I will act on it. I should walk away from the relationship right? I rather admit that I want to have sex with other women and break off the relationship...fair enough right?