I (26M) found my husband’s (30M) nudes and secret reddit account on a NSFW subreddit after years of no intimacy between us. Should I be this upset

My husband(30M) and I(26M) have been together for 9 years and, over the past 2 of those, things have been pretty dead intimacy wise. I gained a lot of weight leading up to that time(~70 pounds) and he later confirmed it was the reason for the drop in sex. I understood as it was not a good look and, while it stung to hear that I was no longer attractive to my partner, it helped motivate me to lose about 50 pounds to date. He has been very supportive of my weight-loss and frequently I felt like he used the potential of intimacy as a tool to further motivate me.

But nothing had changed on the bedroom front. When I've brought it up or tried to initiate things his primary objections are that he doesn't want to be used as validation for my self image and that his libido has fallen as of late. He had never been particularly sexual so I took his word for it. This has been the situation for the past 8 months.

This morning while browsing a NSFW selfie subreddit filtered by new I found a picture of him on an account I didn't recognize. I snooped a little and found out that on this second account of his he consistently messages other NSFW selfie posters seeking to DM and jackoff together on snap chat and the like. At first I thought somehow it wasn't him because both the content and style of speak was so out of character for how I thought I knew him but I'm sure it is his as it also occasionally posts in his unique niche subreddits that i know he follows on his main account.

I feel kind of sick to my stomach and don't know how to handle it. Should I confront him about immediately or wait till I've cooled off as I'm prone to dramatic flair. Should I even be upset if this was never explicitly said to be a problem in our relationship?

TLDR: My(26M) husband(30M) doesn't find me attractive anymore and says he doesn't have libido but apparently has enough of one to horn after strangers in their reddit DM's and snapchat. Should I be upset if this behaivor hasn't been explicitly stated as a redline in our relationship. Should I consider things over given the circumstances or am i letting my body/confidence distort things?