I’m a man in my early 20s and I’ve been in a stable, loving, monogamous relationship with my girlfriend since we were in secondary school. While she is fully aware of my bisexuality (and seems completely fine with this), I would also consider myself polyamorous – which she finds much harder to accept. I frequently have strong sexual and romantic feelings for other people, which I once brought up with her in an attempt to be as open as possible. I wanted to emphasise that this did not detract from my feelings for her. She was initially (and understandably) upset, but seemed happy to stay with me as long as we remained “faithful” to each other. This leaves me in a situation where we are happy together, but where I am left feeling incomplete. I have never been in a serious relationship or had sex with anyone except my girlfriend. The whole world of casual sex and dating is alien to me. I want her to feel as loved and valued as she deserves, but I want more for myself, too. I don’t know whether to feel greedy and ungrateful, repressed and frustrated, or all of these things at once. Labels can scare people, especially if they do not truly understand what they mean. You are both in the very early stages of your sexual journeys, so it could be useful to recognise that you have a lifetime of adult exploration and experimentation ahead of you. Clarification is important. Ideally, you might share more of your thoughts and feelings about your sexual styles and identity with each other, but be careful to do it in a non-threatening way, always affirming your positive general feelings for each other. Try to clearly express your own feelings and beliefs about who you are sexually – taking into account that, while you can be very sure about your sexual orientation quite early in life, when it comes to sexual styles there can be a meaningful difference between fantasy and what you are prepared to act out in reality. Encourage her to express her feelings about whatever you share, and listen carefully to any concerns she might have about your compatibility. Pamela Stephenson Connolly is a US-based psychotherapist who specialises in treating sexual disorders. If you would like advice from Pamela on sexual matters, send us a brief description of your concerns to private.lives@theguardian.com (please don’t send attachments). Each week, Pamela chooses one problem to answer, which will be published online. She regrets that she cannot enter into personal correspondence. Submissions are subject to our terms and conditions: see gu.com/letters-terms. Comments on this piece are premoderated to ensure discussion remains on topics raised by the writer. Please be aware there may be a short delay in comments appearing on the site.