I’m rarely able to cum to my bf

I’m (18f) in an ldr, me and him (20m) haven’t met yet, so we never had actual sex, we only sext or mostly do it over video call.

We’ve been together for almost 4 months now, I’m very happy with him, I love him and he loves me, and I think he’s very attractive, I get horny often thinking about him, and when I’m alone I’m almost always able to cum to the videos he sends me, but when we video call I almost never cum at this point, I get really wet and really horny but I just never finish, and if I want to, it would take me up to half an hour or more in some cases and he’d sometimes be like “why is it taking so long”.

And at first he’d wait for me till I finish even if he had already came, but now, with his busy schedule and all, he just doesn’t, sometimes I feel like he doesn’t really try anymore, he’d sometimes just say “if I was there I would’ve done so and so till you cum but rn I can’t do much”, which is kinda true except that he was able to make me finish many times before, it just took so long.

I don’t know why that happens, I was in an ldr before and I was almost always able to cum, I’ve also rarely been watching porn for months now.

I’m on an antidepressant tho, Escitalopram, I only started it at the end of my previous relationship and since then finishing has been hard and I wouldn’t get horny as often either, I had a very high libido before that.

What should I do? At first I wanted to finish so I don’t disappoint him, but now I wanna finish for me, I wanna enjoy sex too and I wanna do it with him.