Is he a sex addict?

I am sorry to hear about your difficulty and I understand your concern.  To determine if his behavior is addictive around sex, I would have to know more.  Sex addiction is about more than having a lot of sex. Frequent sex is not a criteria for sex addiction. Having said that, a person who needs to have sex that frequently very well might have an addiction.  What it comes down to is not the frequency of sex, but the role sex plays in his life - is he using it to regulate his emotions?

Sex addicts crave sex much like the alcoholic craves a drink to cope with unresolved emotional pain. A sex addict will be compulsive about sex regardless of neglecting other priorities in his life (family, friends, employment academic or recreational).  Sex dominates their thinking and becomes the organizing principle of their life.  They will forgo what used to be pleasurable activities (sports, etc) to continue their addiction. The addict is willing to sacrifice much of what he cherishes in order to continue the unhealthy behavior. When sex is an addiction, the person may make attempts to control or stop their behavior but they find that their anxiety level gets out of control and to regulate it, they continue on with the unhealthy behavior.

At this point, I would recommend the online sex addict self-test. It is free and you will get results immediately.

https://www.recoveryzone.com/tests/sex-addiction/SAST/index.php

I hope this helps. Let me know if you have other questions.