Boyfriend is tired of sex

My boyfriend and I have been dating for about six months. For the first couple of months everything was great, we spent a lot of time together and had a lot of sex. Now, my boyfriend has been very uninterested in sex and for a while he has told me that he’s just going through a “phase” where he’s not horny, which, I figured, was completely okay. HOWEVER, Yesterday he told me that wasn’t true and the real reason he doesn’t want to have sex with me is because he is tired of sex and thinks our sex is boring and that we do it too often.. He also said that he wants to “try something new”, but that he doesn’t know what.

I’m torn - should I just go along with this and say okay, we’ll do it less? Or does this mean that it’s gonna stay like this? Because if it does, our relationship is not gonna last..

Please help!..