I agree with Derby. I feel you need to make a relationship work before you add more people to it - be it a poly relationship or, for instance, having children. Any issue gets only worse when there are more people involved.
I'm afraid it would be a bandaid solution that would make you miserable in the long run, so I would definitely encourage you to find other solutions to your problems if you can.
Me: 31F, straight
Seamus: My husband, 32M, straight
Dragon: My boyfriend, 29M, pansexual, married to Fox
Fox: My boyfriend, 29M, homoflexible, married to Dragon