Should I believe him or not?

I have been married to my husband for 26, going on 27 years this coming June. I am 58-think I am going through menopause. Don't feel attractive--have put on weight, hair thinning, don't feel I look like myself anymore. Been through some struggles the last few years with kids, my job and pets. I am currently unemployed-I quit my stress fest job in August.

So, cut to the chase--we haven't been as physically close for the last few years. Sex is painful-I am trying to "fix that" with hormone creams and possibly trip to the doctor. In the meantime in the last couple of months ago (November) my husband would come home and be "frisky". Sometimes we would have sex, sometimes not. Sometimes if we did he would lose his erection during. He is on high blood pressure meds so I tried to not make a big deal about it since I know this can be a side effect. I did ask him if he still "liked" me and he said of course that he didn't know what was wrong-maybe he had drank too much beer or took an antihistamine etc.
Anyway, I was starting to feel the fog lift a little in October/November from the stress that was gone from my job I think. Starting to feel more like myself. Then I just started getting a "funny feeling" --I call it my esp when something is wrong with my husband or kids. The night before Thanksgiving, my husband's phone made a noise and it looked as though our son had tried to text him. Since my husband was in bed asleep, I looked at the phone and the browser popped up with porn pictures on it-several. I just felt sick and tried to go to bed and sleep after I figured out it was not my son trying to contact us. The next morning I confronted him about it and he said that since his cell phone (work issued) is tied to his computer (at work that anyone who was looking at stuff on his computer, it came to his phone and maybe it was one of the single guys out at work. He assured me it wasn't him and that he loved me etc...But it just sent me into a spin. I asked him if he had been looking at those pics before coming home extremely frisky a day or so earlier and he said no and when i pushed the subject he went to his truck and brought in an expired sample bottle of Viagra that a guy at work had given him. He said he got it so he could keep an erection with me since he had been having problems with that recently. I scolded him about taking drugs that his doctor doesn't know about (he has kidney issues). So he apologized and we just carried on--me on the (hopeful) assumption that the porn was someone else's and the Viagra was "for me." That was Thanksgiving. Fast forward to December--a few days after the 8th-I don't remember which day. He left his phone on the table after he went to bed and I admit I looked at it. In his text messages nothing out of the ordinary except a text with some sort of confirmation number from Adult Friend Finders dated December the 8th at 12:33am (he goes to bed early-8ish and is up by 5am and he wasn't on his phone after he got home about 3:30pm). It didn't mention any name. It just said something like "congratulations here is your activation (or confirmation number-can't remember) . I immediately woke him up and asked about the text and also some of the porn was still on his phone browser history-same stuff from before-it didn't look like anything new. He said he didn't know what it was probably some spam text or something and that he hadn't been on that Adult Friend Finders site. He keeps telling me he loves me and nothing is wrong etc. But I just can't get over this. I Googled to try and see if his computer browser could be linked to his phone--his Google is linked but from what I can tell his phone's web browser is not-I am not real tech savvy though. I went on and made a non-paid false Adult Friend Finder account and I check that all the time. It is disgusting all the married men on there. I found one user name that "could" be his but unless I pay, I can't find out any more and to do that I would have to enter credit card info on there. I just may get one of those Visa cards you buy at the store to sign up. But I can't sleep now, I am up every night trying to find a logical explanation to all this or damning evidence. Last night was the worst--I was worried to death about our son who we thought had a hernia but they can't find any hernia and has lost a lot of weight over the last few months. I have anti anxiety pills but had to take three to get me to sleep and now I feel awful. I just feel awful anyway. Unattractive and awful. I keep thinking "what if the Viagra was to use with someone else-maybe from Friend Finders?" He hasn't wanted sex hardly at all since and I don't want to pressure him because I don't want to hurt his feelings if he has erection problems. But are the erection problems because he isn't attracted to me anymore or because of a medical problem? Either are scary. He says he loves me and said the porn wasn't his nor did he go on Friend Finders. I can't check records etc because both his phone and his computer are work issued and his computer is at work--he doesn't use the computer here at home. So I don't have a lot of avenues to research, do I? Please read the suspicions and give me your opinion--maybe someone else has had something similar happen? I just don't know what to do. Like today I woke up and just thought I should tell him I want to separate. My kids 25 & 22 would be devastated especially my daughter. I just don't want to get to the point where I am DONE and don't care anymore. Right now I am hurting but there are moments of anger that have been showing up this last month and I know myself--when I am hurt I get mad and want to be as far away from the thing that has hurt me as I can get. I just wish I could erase the last 2 months.