Do you find untrusting usually means untrustworthy?

This will take a minute to explain. (I've talked about some of this before, but I'm asking different questions this time. I'm putting the main points in bold.)

I was straight (i.e., zero interest in any guys ever) until last summer when I became attracted to another guy for the first time in my life. We've been together almost a year.

When I met M, he was married with a four-year-old son, and was looking to jump-start his social life since his wife his been keeping him pretty isolated. We started hanging out and he told me about his marriage troubles, how they'd decided it was over after trying to make it work the past few years, and he was just looking for comradeship.

I told him about my recent romantic plights: My ex-girlfriend cheated on me with two of her exes, got pregnant, told me the baby probably wasn't mine, and left me.

We bonded quickly. One evening as I was leaving his house, I felt this compulsion... I really wanted to kiss him. So I did. And he kissed me back. We both decided that we'd date after that, and we've been together ever since.

But when we first became romantic, we kept our romance a secret. Neither of us had had a same-sex attraction before, so we wanted to figures things out on our own before we revealed ourselves. It stayed this way for about the first three months of our relationship; not even his wife knew.

Over those months, I worried a lot about him still living with his wife. I wondered if their relationship was really over, or if he was "with" us both. I knew that, aside from him still living with her, I really had no reason to doubt him; I could tell he loved me even by just the way he'd look at me. I had no doubt of his feelings, but I couldn't help but wonder if the possibility that they were still sleeping together was a legitimate worry to have or just paranoia. For the most part, I ignored that part of me that said this was too good to be true and he just had to be sleeping with her still.

One weekend he told me his wife would be gone and asked if I wanted to come over. I packed a (HUGE) bag and went to stay with him. When I got to his house, we immediately ran up to his bedroom and had sex for about three hours, then got in the shower.

As we were showering, the front door opened: His wife came home unexpectedly and, literally, caught us with our pants down. He left the bathroom (where I was "hiding") to talk to her, and she told him she wanted us to get dressed and come downstairs to talk to her.

As we were dressing, he said something that struck me as odd. "She's going to say things, things that aren't true. She just wants to hurt you and come between us." Given the situation (his wife waiting for us downstairs) I didn't ask him to elaborate, but what he said definitely stuck in my head.

When we went downstairs, she asked us how long this had been going on, if we were serious and long-term, and said she just wanted their son to have a normal life with no unnecessary hardships. I told her we weren't going to be lewd around him, but at the same time we wouldn't want him to think that our relationship is something to be ashamed of or wrong; she agreed with me. Then she hugged us both, welcomed me to the family with a smile, and left.

That happened in mid-November. Since then, M and I have definitely had our ups and downs--the downs mostly related to things he found out about me from others and felt I'd been keeping from him, but we've been working through that and we'll end up stronger for it once it's all said and done--but I'm finding that he's always super paranoid that I'm lying to him and keeping things from him.

One night I was in my living room watching TV and glanced absently out the window. In the dark I could see the silhouette of a person moving just outside the window. It scared the shit out of me. Then I realized M had been texting me, asking me very specific questions and asking repeatedly what I was doing. So I wondered... is that him spying on me outside? I jumped up and walked out and saw the figure run across the yard and hide behind a tree. When I went over to peek behind the tree, there he was. And at first he acted all huffy and pissed off like I'd been doing something wrong and tried to walk off and leave. I pleaded him to stop and talk to me, asking what was wrong and what he expected to catch me doing. He conceded and said he had no idea why he was outside my house that night. We stood there hugging each other for about 15 minutes, then he left and went home.

I understand some of the mistrust I brought on myself when he was told things about me (most of which wasn't actually true) back in February, but he's been going through my phone and driving 40 minutes to my house to drive by and see if I'm home when I say I am since a month or two into our relationship before we ever even had our first argument.

And it just reminds me of something I'd heard once, although I'm not sure who told me this little nugget of wisdom... "Those who are the most untrusting are the most undeserving (or unworthy) of our trust." And I take that to mean if someone is super paranoid about others keeping secrets, it means such a person probably has some big secrets of their own, which makes them assume everyone else is hiding things too. Do you find that to generally be true? Or is that just part of his personality, to be skeptical of others, especially a lover?

All things considered, I've been very happy with my boyfriend, and things have been really good again lately. We did have a bit of a fight last week... I told him I was at a doctor's appointment, and apparently he drove by my doctor's office to see if I was there and didn't see my car. We had a huge fight about it. I promised him I really was there and have no idea why he didn't see me; I also said he can't keep punishing me for mistakes I've made, ones made way before I met him, and that I don't hold anything he's done against him so he should extend me the same courtesy and give me the benefit of doubt.

So we're okay again, but I do think about this a lot. His wife knows about us now, but he reaction to when we went public on Facebook in January was pretty negative. She told M that she figured I was just a phase or an experiment, but that ultimately she always figured they'd get back together; when M and I went public with our relationship, she felt like that was the moment when their getting back together would not be possible.

And he's talked to her about all the problems he and I have had since, according to M, she's now like a friend/roommate (who sleeps in the same bed with him still). So I worry sometimes that she still sees me as temporary and is just waiting/hoping M will come back to her. And that makes me wonder if M feels the same way. And then I worry about when they're home together or that they still sleep in the same bed. She's fully aware, especially after catching us in the shower, that M and I have sex, but how much would that stop her from trying to get back together with M when she's expressed such disappointment that that might not be possible before?

I do worry a lot about all this. What if he was still sleeping with her while dating me, either now or before? There's really no way for me to know for sure. I've never treated him differently as a result of my worries or been untrusting of him, but sometimes I wonder if I'm not being naive. The fact that he's so untrusting of me doesn't help matters.

Any feedback would be appreciated. My apologies for being so wordy.