Hi memory lane
I'm wondering if what your observing or witnessing is your partner not managing COVID lock down effectively.
If you naturally excite him and he's not seeing you, he would need to manage his lack of excitement. A serious lack of excitement is serious, as it can be depressing. If you naturally create a form of stress release for him, without you spending time together how would he be managing to release stress? I could go on in regard to how you may be a natural form of positive therapy for him but you get the gist. So, what you could be witnessing in him is him seriously missing you and it could literally be depressing him, on top of all the stressors he's facing.
I'm wondering if creating things for him to look forward to will naturally excite him. Making plans for when you reconnect could get him worked up to excitement, raising his spirits. If he has a good imagination, planting images in his head involving a picnic on a nice sunny day with a bottle of wine and a bite to eat, at a place you've dreamed of going together, could do the trick. Getting him to imagine you in a new outfit that you bought especially for when you reconnect might be another thing. The imagination is a powerful thing; once activated, it can change our mental and physical chemistry. It's incredibly powerful at times.
If he can't imagine any positive difference throughout this COVID challenge, what he imagines in this case will also impact his mental and physical chemistry. If what he imagines is depressing, this can have an impact in a number of ways.
I've found 'feelings' play an important role in how we connect to life and each other. Feelings aren't often addressed as 'physical emotion' (energy in motion) but when they are, we definitely start to notice how we feel. So, if I said you have the power to change how he feels (life), how does that lead you to feel? I imagine excited, even if it's just a little. Can you feel the excitement in your body?
Part of the challenge here may simply involve you raising your partner to excitement. Can't hurt to give it a go. I imagine you'll naturally be able to pick what makes a difference to him and what doesn't. If a lot doesn't make a difference, don't give up searching for what does.
Good luck :)