Need to vent but am I alone?

I’ve been with my boyfriend 3 years. Sex went from amazing to almost non existent now. He suffers from depression and anxiety so I’m trying to be patient. He’s always suffered from this and maybe it’s stronger now. This is his excuse for not being in the mood, but yet he masturbates when he gets a chance like once or twice a week. I know sex is tiring and masturbation is just easier. But I can’t help but feel a certain way. Is this normal? Like does he just need that release? I’ve asked if he’s just not attractive to me anymore and he swears that’s not it. But porn gets him going to masturbate. Can anyone relate or give me advice. Also I do have a high sex drive and he knows this. I do masturbate myself but it’s not the same. And yes when we talk about this we argue and it’s always that he has other things on his mind sex it not one of them.