There are ways to be monogamous and keep it from being boring - see my story that I linked to you last comment for more about that - but chances are you don't have a good sense of what pushes your partner's accelerator and what stomps on her breaks. Sexual boredom is only one of the possibilities.
Nagoski points out that when researchers ask them, “What gets you in the mood?” women say:
Having an attractive partner who respects them and accepts them as they are
Feeling trusting and affectionate in their relationship
Being confident and healthy — both emotionally and physically
Feeling desired by their partner, being approached in a way that makes them feel special
Explicit erotic cues, like erotica or porn, or hearing or seeing other people having sex
But what these answers tell us, too, is it depends. A woman who feels confident in herself, and who is in a great relationship with a partner she loves, trusts, and feels attracted to, still may not want sex if she has the flu, worked seventy hours that week, or prefers that both she and her partner be freshly showered before sex and they’ve just come in from doing yard work together.
