If you want to keep a healthy threesome relationship for your partner and yourself, you should focus on the following points. Firstly, you should communicate with your partner more often. No.2, trust your partner completely. No.3, be honest to your husband/wife, boyfriend/girlfriend. The three elements are very important for having a healthy relationship, especially for couples looking for men relationships. Since a bisexual relationship is much more complicated than a common relationship.
Let's start with communication. You should come out to your partner with an open dialogue. The best time to talk to your partner about being bisexual is whenever you feel ready to. And please remember that your identity is legitimate — regardless of how your partner identifies — is a difficult but very important practice. Hiding your sexuality might ruin your relationship. If you tell him/her you are bisexual, your partner may be supportive. If your partner finds out the truth that you are a bisexual woman/man and you didn't tell him/her before, he/she will think you are cheating on him/her. Your relationship could be broken.
If your partner is a bisexual person, do not doubt him /her. Some people are worried that they might be abandoned by their partners. Some people will be the jealousy of their partners to love both genders. Jealousy is not a healthy element in a relationship. You need to know that he/she chooses to be with you, that is because you're his/her only one and true love.
You should be honest with your partner. Tell him/her your needs. Some bisexuals don't know if they should tell his/her partner when they are attracted by the other gender. I suggest you confess your real needs to your partner, listen to his/her opinion, and discuss this situation. In fact, many partners will be open-minded for accepting. (I found lots of bisexual couples, one is bisexual, the other one is totally straight. The straight one is very supportive of his/her partner get involved in a relationship with another gender.) If your partner is against it, try to remember that he or she will have been on a really difficult journey. You'd better find another way to achieve an agreement. Do not cheat on your partner. It matters not so much whether you can or cannot understand, but that you accept your partner’s thoughts and beliefs as their own, and valid to them. Take it from me, you won’t be able to change each other, but you can help each other to feel more hopeful of a meaningful future.