Some people are happiest in monogamy, and that's okay. If your partner is monogamous, that isn't a rejection of you, and it doesn't mean your partner is unevolved or unenlightened. It may, however, mean you have to make a choice: how important is polyamory to you? Can you be happy if your partner wants you to remain monogamous for life? If not, you may be faced with ending the relationship.