Sorry to disagree. I am poly; I am deeply in love with my vanilla spouse, who is aware of our situation. She knows and loves my subbie, who feels the same about her. I am deeply in love with my subbie, who is a totally different person from my spouse.
Re: loving more than one person. A favorite author says, "I think it is possible for a person to love all the majority of good and caring people (who walk the earth)." I have loved many thousands of people, employees, co-workers, clients, customers. There are 'degrees' to love, if you will; some deeper, some more shallow. But the inner circle, my immediate family, spouse and sub... well, that love is equal and as rich as can be.