There are no limits to the people you can love. Your heart has no limits.
From a multidimensional perspective you are simultaneously in love with so many people!
Of course, you can have moral and spiritual values about your intimate relationships, and being loyal to one person at a physical level can be a powerful expression of love.
On the physical level, do what you feel is appropriate, respecting your values and those of the people you relate with, but do not allow your heart to close at other levels.
Our separate identity thrives on the conflicts created in your heart. It is based on love scarcity and competition. If somebody loves more than one person, then there is a problem, there is not enough love available. Hence the top achievement in this delusional world is to have exclusive love. The point is that true love is inclusive, unlimited, unconditional.
Whether you are monogamous, polygamous, single or in a state of chastity, what matters is that you keep your heart open.
Never allow the love you have for someone to sacrifice the love you feel for others. There may be good reasons to be faithful to one person in the intimacy of physical love. But if you impose yourself, or are forced, to give up the emotional, mental and spiritual love you feel for others, this is the most cruel thing you can do to yourself and others, including to your exclusive partner.
You are here to open your heart, to expand, to learn to love more and more people, to understand that everything around you is part of you. Ultimately the more you love others, the more you love yourself, including your exclusive partner, if you have one.