There's an expression on here which is that depression doesn't make you a twat.
There is so much wrong with this guy that I am amazed you are still trying to defend him.
It went from him texting or calling me (evenly balanced) to me always texting or calling, often he won't reply or answer the phone. (this is just bad manners and a sign he’s not interested in you)
I'm always the one arranging things and mostly we just stay in, he doesn't want to go out (this sounds very unfair and boring)
he hardly speaks to me anymore (that must make you feel depressed and lonely)
when I do speak I'm told what I'm saying isn't interesting (don’t you find that very hurtful?)
his favourite question is "is what you're about to say going to interest me" and then I'll be told a more interesting story from his life (this is NOT the sign of a depressed man)
I've seen him texting another woman we both know, she keeps asking how he is etc but he keeps saying she's asking him for favours. He says this a lot, and I know he's lying to me (lying is a massive red flag – what does he have to lie about? You’re not stopping him having friends)
We aren't having sex anymore, which I understand is a side effect of depression (it’s also a sign of lack of interest or a lower sex drive or any number of things)
he's not on any medication, nor is he seeing a counsellor or equivalent (so he’s not actually diagnosed as depressed? He’s also not willing to help himself)
He's told me he's busy most days this week so I've had to leave relatively early each morning (inconvenient for you, then)
yesterday I left then about an hour later had to drive past his house (it's on a main road) and his car was still outside, he told me he was leaving straight after me (so he lied to you and made you get up earlier than you needed?)
I love this man (I don’t know why you would, based on all this)
I know he loves me (I’m not sure how you come to this conclusion)
I feel like a burden in his life and by wanting to see him I'm adding to the pressures in his life. (I would hate to feel this but would be tempted to leave him to let him recover)
I talk to him about a situation that upsets me and I'm told I'm making him feel pretty shit (absolute and utter selfishness)
He's begun to make me feel so crap when I'm with him (read this again and again)