I have a few paying customers, but am struggling to grow

I run a SAAS similar to Habitica (social gamified productivity). Three months after launching, I have 10 paying users ($20/month) who use my platform religiously (8-10 hours/week). I have 200 free users, but most of them log on once a week or less. Growth has been slow, nothing like all the founders who celebrate hitting thousands of signups the first day. I've been iterating based on feedback, and I sincerely believe my product has improved tremendously as a result. But still, the #1 complaint I get is there aren't enough people online. My retention rate is 3.5%, so I experience little return for the small amount of time I can spare for marketing. I spend the entire day answering emails and iterating (writing code) based on the valuable feedback I'm receiving, which leaves almost no time to spend on marketing. I'm just discouraged with how slow my numbers are increasing. I'm a solopreneur. Should I hire a nontechnical cofounder/assistant? Or, will the growth take care of itself after I've reached product-market fit?