Should I tell my partner that his cousin is trying to hit on me

We been having problems and work for both of us is hard to find due to the weather because he works outside and I have no experience in big business so it is hard to find for me

I talked to his cousin asking him if he knew a place that was hiring, so afterwards he started to text me everyday and started to hit on me in different ways and I just feel very uncomfortable about this situation. Started to say he wish he can kiss me but says that his cousin will kill him if he does and also asking if his cousin and me are having sex and I just ignore it

Update01/30/19 : told him yesterday and he was so confused about the situation and he was putting everything together