My significant other and I are struggling but he refuses to come into therapy with me. Is it worth me coming in alone?

Absolutely! Ideally you would like for both individuals involved in the relationship to come in together to and work through mutually identified problems.  However, in the absence of a willing partner, positive change can still take place when only one person comes into therapy.  Any change one of the players makes will inevitably affect the other person and thus the relationship. Over the course of time, typically one’s partner sees the positive growth his/her significant other has made and eventually engages in the process themselves.