Strikingly.com is pretty good. Wix is also good. Squarespace also good.

I hope you are specifically interested in Partner Marketing practices which is being said according to your question.
But later looking at the detail you are diving deep into affiliate kind of model where you want to work with Promotional Partners.
Let me tell you both Referral Marketing and Affiliate Marketing are different models to work with, which falls under Partner marketing. Here are few differences:
In affiliate marketing the advocate doesnot know their referred customers personally, and the primary reason for referring your brand is financial motivation.
Whereas, Referral marketing advocates recommend your brand to direct friends or family members and motivation is based on a strong relationship between the advocate and the potential customer.

Both of the above practices under Partner marketing have different approach to hire the partners and work with them. It also depend on your stage of company at which they want to deploy which practice / strategy.

Further you can use these tools:
Hasoffers, Cake, Getambassador, OSI Affiliate Software, Offerslook to create individual Partner Marketing Site for your product / service promotion. Go for their whitelabel solution and using them you would be able to create Partner Marketing Site.

WordPress is the most popular platform and it also better works for Search Engine Optimization.