Boyfriend said he’s not turned on by me?

My partner and I have been together about 6 months, his sex drive is a lot lower than mine meaning we only have sex about once a week max. We were having a wee bit of an argument a few weeks ago and he told me “I don’t know how to say this but I’m just not turned on by you, it’s not you I just don’t really feel turned on by anyone or anything”. I don’t really know what to do or how to act? I’m too shy to initiate anything now cause I feel I’ll be rejected. I thought it could just be to do with the sex drive thing but while I was at work the other day and he’s been off with covid, he told me he masturbated 4 times in one day which really upset me. I’m not against pleasuring yourself I do it too! But when we’ve not done anything in a couple weeks and he’s doing that it makes me feel a bit off. What should I do?