There is a new polygamous dating site, polygamy.com, that started this year, based in the UK. I have not used it, I don't know whether it will be successful or not, but it has been getting some mainstream media coverage.
Be aware that this has been established by a Muslim man, as a sister-site to the Muslim-specific dating site secondwife.com. Polygamy.com is his way of reaching out to the secular world to normalise polygamy, from the perspective of a Muslim wishing to encourage the West to accept Islam. This does not necessarily mean that polygamy.com should never be used, but it is a very important point to be aware of for anybody considering using the website.
Be aware that this has been established by a Muslim man, as a sister-site to the Muslim-specific dating site secondwife.com. Polygamy.com is his way of reaching out to the secular world to normalise polygamy, from the perspective of a Muslim wishing to encourage the West to accept Islam. This does not necessarily mean that polygamy.com should never be used, but it is a very important point to be aware of for anybody considering using the website.