The overlap, and why it confuses people
Almost every sexual problem has a relational layer, and almost every relational problem eventually shows up in bed. That is why titles blur. The practical difference is training and default lens: a relationship expert will look first at how you treat each other, a sexologist will look first at how desire, arousal and shame are working, then at the relationship around them.
How to choose in one question
Ask yourselves: if the sex was suddenly great, would we still be unhappy? If yes, start with relationship work. If the answer is no, and the friction is really about frequency, pleasure, pain or things you have never said out loud, a sexologist will get you further, faster, because that is the specialist subject.
What to check before you book anyone
Ask about training and certifying body, whether they work with individuals or couples, how many sessions people typically need, and what happens between sessions. In sexuality work, AASECT certification means supervised training and a binding ethics code. Anyone unwilling to answer those questions plainly is not the right choice.
What working with me looks like
I'm Dr. Amber Mallery, an AASECT certified sexologist and TEDx speaker. I work online, individually and with couples, in ninety-minute sessions, and I take the relationship seriously without making the sex an afterthought. Every session ends with something you can actually use: a script, an experiment, or a decision. If what you need is clinical mental-health care or medical treatment, I'll tell you and point you there.