Open sexual relationship, can you truly love your SO?

So this scenario doesn't exist in my life but I think it's an interesting topic to discuss and I want to know what you ladies think. I'll be using myself as an example though.

So I have only ever have real sex with my SO. For the past couple months I've been thinking about exploring my sexuality.

If my boyfriend and I decided to open our relationship to casual sex, would we still truly love each other?

Or do you think true love only exists in closed, fully committed relationships?