Many of us identify as homosexual, bisexual, pansexual, or other identities that are liberal in the sex and gender of our partners. This is often difficult to understand for people who are not bisexual, whether they are homosexual or heterosexual. This is a guide for monosexual partners (clarification: someone who is either heterosexual or gay) to be a better lover to bisexual partners.

1. Manage and be aware of your jealousy, even more than in other relationships.
Many people experience jealousy in their romantic pursuits, which is normal as long as it is controlled and does not affect the other person. However, bisexual individuals in their sexual orientation and activities might be interested in anyone, and being suspicious of them when they hang out with someone will severely harm your ability to have friends. This is really important to remember and also to balance with the following two points.
2. Remember they are bisexual or liberal, and you need to take this sexual orientation as seriously as you would a heterosexual or gay orientation.
Many times I've been with partners who forget that I'm bisexual and become fiercely jealous of me being around people of a particular sexual orientation, but treat others as normal friends. Really? My current partner understands my bisexual orientation and knows that women, or any other gender, can be as much a threat to our relationship as he is. However, I've also dated people who seem to think that bisexual women exist for their amusement. Others, of any gender, believe they are confused. Even if your partner is confused and reconsidering their sexual orientation, it is up to them to decide how to identify it. You have no authority to tell them what their orientation really is.
3. The dating pool for gay people is small, especially in some regions of the country and the world. Don't panic if your partner frequently meets up with an ex or two unless they give you a reason to do so.
This is important for heterosexual people dating bisexual individuals. If there are 10 lesbians in your town, your partner will inevitably run into one or several of them, and after breaking up with them, they might meet or even become best friends with them. That's okay. Think about your ex-partners—do you really want to get back with them? Most people would say no. There's a reason your partner is dating you and not their exes. It's important for us to know other bisexuals or even strictly gay people to understand this essential part of our identity. Sometimes that means becoming friends with ex-partners in a way that heterosexuals might not.
4. Avoid cliché questions as they have been asked about these issues over and over, unless they open the conversation, and don't assume your partner fits stereotypes.
"Who have you had more or better sex with?" "How many threesomes have you had?" These and other common questions for bisexuals are not a good way to start a relationship with a bisexual person. These are questions we've heard a lot. We don't want to hear them from our partners either. In fact, my partner is the person I complain to the most about these questions and stereotypes. Bisexual people in the sex and gender of their partners are stereotyped as confused, promiscuous, unfaithful, and many other things that are not true about us from what the general population believes. I can't count the number of times I've heard people who claim to be very progressive make comments like, "I hope my partner isn't bisexual. I don't want to be cheated on with ____." These comments hurt bisexual people and perpetuate negative stereotypes. Don't assume your partner will cheat on you just because they are bisexual.
5. But talk about it. Ask your partner how you can support them.
Your partner has a sexual orientation that is commonly misunderstood and largely invisible. If you're a heterosexual partner, your partner might love heterosexual romantic movies—but they might also love gay movies. Make sure to ask your partner if there are more things you could do to support their sexual orientation. If you're in a gay relationship with a bisexual person, consider buying them heterosexual erotica. If you're in a heterosexual relationship, go to Pride with them, or encourage them to attend LGBTQ events with their friends.
6. Don't overwhelm them with unnecessary support they don't ask for or want.
This guide might seem contradictory, but it's mostly a matter of balance. It's important to support your partner's identity, but it's not their only identity. Don't treat it as more important than other parts of them, especially if you don't think it's that important. Some people, like me, are very open about our identity and talk about it a lot. However, my gay identity is as important as my working-class, woman, and feminist identities, which I spend a lot of time thinking and talking about. Don't focus solely on their bisexual orientation and not at all on other identities. If your partner tells you they don't want to go to Pride or receive heterosexual erotica, don't force them. Your partner might not want or need any additional help from you, and that's okay too.
If there's something I've forgotten or you'd like to add, please do so in the comments!