Just drinking buddies. Why do I feel like puking?

The last time our relationship was this bad, my then-fiancee/now-husband went looking online for someone to have an affair with. When I found all the evidence, he heartily and profoundly denied it at first, feigning offense that I would think so poorly of him. When he finally admitted that the ads I found were indeed him, he apologized, but eventually "got sick" of me bringing it up and "using it as an excuse" for future insecurities. He said it needed to be done and over with so we could move on. This was within WEEKS of the incident.

I forgave, I stopped bringing it up, but I never forgot.

Our relationship is BAD right now. We'd been working fairly opposite shifts until he got laid off two weeks ago, had been taking each other for granted, have both been depressed for a while now. Between my depression and anxiety, our opposite shifts, our weekend lethargy, and my issues with my plumbing, I have had absolutely no desire for sex. My plumbing has let me down with absolutely no warning on an almost weekly basis for over a year - yeah, really makes you want to be intimate when the sheets could wind up looking like a murder scene at any given time. There's a damn sexy thought right there, isn't it?

We're good for something every once in a great while, but there's no actual sexual intimacy - I can't get into it because I'm just not interested because I'm petrified I'll ruin it by bleeding everywhere, he can't get into it because he feels like he's making me do something I don't want to do (and conversely, never initiates anything because he feels like he'd be pressuring me, and then is always splayed out on the couch, playing video games in his underwear). And now he's having trouble finding me sexually attractive because I talk too much about my plumbing issues, when I thought that letting him know what was going on would help serve as an explanation as to why I wasn't in the mood. But it wasn't until I pointed out to him that he's always in his underwear on the couch playing video games that he realized this is not all MY problem. Underwear/couch/video games is not a bone-jumping combination, you know? So we've got my depression and anxiety, my plumbing issues and the accompanying stress, his lack of motivation and reluctance to start anything to even TRY to get me in the mood, and the whole couch/underwear/video games thing... we're hot. A hot MESS, and he's officially deemed this a sexless marriage.

He went out with some friends from work on a Friday night a couple of months ago, came home tipsy and told me that he found himself attracted to one of his coworkers. I was not surprised in the least - I've known that would eventually happen since the first time I met her, over a year ago - she has the looooong hair and big eyes that he loves (though she's since cut the hair and is now growing it out again), she looks good in those adorable black-rimmed librarian glasses that look awful on me. She's kind of a tomboy, kind of athletic despite being a little chunky, likes gaming stuff and comic books, she creates things that are more worthy of deviantART than scrapbook.com, reads sci-fi and fantasy, and part of her decorating scheme includes video game posters and action figures. Most people who know my husband would probably start to wonder if he was okay if he wasn't attracted to her.

The night he told me he was attracted to her, he said that it freaked him out, because he'd never in our entire relationship been attracted to someone else. In the same conversation, he told me he doesn't know how much longer he can go without sex before he starts looking for it elsewhere or if he'll be able to control his actions when he's out at the bar with his friends.

Cue coworker's desperation. She and her man broke up over the summer, and she's been desperate for male physical contact. She's been obsessing over a guy she met online. Hubby likes to try to fix broken people (maybe that's why he's bored with me, my brand of crazy is just beyond his repair capabilities). He's spent almost every Friday night hanging out and drinking with her for two months. He's since told me that he's no longer attracted to her because she's whiny and desperate, but he keeps going out with her, rolling his eyes as he leaves the house, saying that he'd rather not, but that he said he would, so he has to. I'm uncomfortable with him hanging out with her, but when I mention it, he rolls his eyes, sighs heavily and says "so are you the jealous little wife now, who won't let her husband have female friends?"

This past Friday night, he had way too much to drink and I had to go pick him up at the bar. Part of the way home, he fretted that "the girl he fancies figured out that he fancied her." So while I was sitting at home bleeding like a stuck pig because of medication I'm on to help regulate my cycle so we can try to have a baby (not that I was invited to go out anyway - I've expressly been told that Friday night is his night out and I should stay away from "his bar"), my husband was out worrying that the girl he has a crush on figured it out. And this is what I had to listen to on the way home. Depressed, anxious, hormonal becuase of the medication I'm on, and I'm captive to my husband's worrying that his crush figured out he liked her.

And now, since we're in a sexless marriage, he's brought up the possibility of making this an open relationship. Because we're not having sex, and he needs sex to be happy.

Let's boil this down...

• He has a crush on her.
• She's desperate.
• He's a big flirt when he's drunk and self-admittedly might not be able to control what he does in the vicinity of attractive women after he's had a few.
• He goes to have a few on Friday nights, with the girl he has a crush on, at a bar where it would just cause more problems than I need to deal with if I were to show up unannounced (I've already gone there once on a Friday night - with a friend who suggested it - and got accused of "checking up" on him - when he got there he said "you know this is my bar, and I'm here to meet my friends and am going to ignore you all night, right?" He later said to me it was supposed to be a joke and lighten the mood - but it did nothing of the sort)
  
• He wants an open relationship.

Why do I feel like I'm being groomed for the inevitability of an affair? Whether it's with her or not, I've got this sinking feeling in the pit of my stomach that he's going to go out and do something stupid and tell me that it's my fault, and that I shouldn't have the nerve to be hurt because I should have seen it coming.