How Often Do You Jerk Off? (Advice Needed)

I will preface this by saying that I've always struggled with insecurity around fulling trusting a partner - With that in mind, I'm genuinely looking for advice and/or constructive discussion around this: How often do you masturbate (without a partner).

I (late 20's) ask because my partner (early 50's) seemingly does so any chance he gets - Especially when I leave for a work/other quick trip, or when we work different schedules. I know because, for most of our 5+ years together (4+ living together), I've done a bulk of our laundry, and have often found cum-stained boxers, and - Upon returning from trips, crusty socks on the floor, when I know my partner rarely wears socks around the house.

I also ask because, I've always made it clear that I am up for anything with my partner, at any time; that I have a fairly strong sex drive, and that I will always prioritize his feeling good and satisfaction during sex. And also because, as to part of what initially fueled my insecurity - He often had/has a habit of following tons of thinks (mostly amateur sex workers looking to grow their content), across most of his social media pages. I know, I shouldn't have looked at his following lists to begin with. But since (first discussed this with him nearly 5 years ago), I've always had a hard time feeling as though: a) I can not fully trust my partner; b) I'm not truly desired by my partner; c) I'm not a priority for my partner; and d) I'm absolutely shorting myself and receiving the short end of the stick in return (no pun intended).

I know it's silly, and I will also add that I struggle with diagnosed OCD, so ruminating is something I struggle with (I'm in therapy) - But these things (the constant masturbation and what feels like eyes for other boys) have eaten and eaten at me, throughout our relationship. Discussions around this don't seem to actually resolve or change anything.

Am I overreacting? And if so (or if not), how should I approach this, or maybe grow so that I'm not nagged by it?

Thanks in advance to all of you who took the time to read through this!