Can bisexuals have a normal relationship?

absolutely. Somebody that is bisexual simply means they like both sexes. Just the same as if someone who is just heterosexual but is attractive to different races. People fall in love for the person they are with. Just because you are with a bisexual does not mean that they will run off to someone of the opposite sex. For men who are in a relationship with a bi sexual girl, it can actually be more fun and exciting, depending on your needs. Most men, do not mind when they see 2 women going at it together and if the girl is bi sexual, you have higher chances of encountering 3 somes. Again this is not always the case and the 2 should always talk to each other first before encountering in anything like this. But to sum it up, Yes, a heterosexual can have a relationship with a bisexual, even without the 3some factor. If someone is going to cheat, they will do it regardless of being heterosexual or bisexual. If they are are faithful, they will be regardless of their sexuality too