I just discovered last night that my FTM partner is trying to solicit man for sex out of Craigslist.....I'm broken, angry, sad....

I'm not surprised you're angry.

please someone, please explain that to me: we met few years ago...back then "she" was only dating girls....I was very supporting partner with the transition...i was very supporting partner when he got diagnosed with asperger's syndrome....learn how to talk in his aspie language...we had good personal and sexual relationship...and I just discovered his add on craigs list looking for casual encounters with a man... is it testosterone or aspie obsession?

Neither, its just poor behavior.

Confront them.  You don't deserve treatment like that.

To agree with sarah, cheating is cheating.

Adultry of any kind is just plain mean.

I agree with everyone else here. While he may be becoming more curious about men (he is at least bisexual, perhaps he is realizing he is gay), this is not an excuse for cheating. If this is something that is genuinely on his mind and that he wants to explore, as your partner, he should be completely open and honest with you, even if he fears your response. It's not only about emotional integrity, it's about the fact that if he is sleeping with strangers he could potentially be putting you at risk to catch a disease. Protection isn't always foolproof.

Confront him. This is no different from if he were cheating on you with another woman. You deserve better than this and you have every right to be angry, sad, and scared.

Oh my, soulofgypsy, I'm so sorry you're having to go through this.  Everyone is right...I don't care who your partner is, how he identifies....cheating is cheating and NO ONE deserves that.  Your partner owes you the respect to talk about these things with you or to break up before any encounters with another person.  Whether someone is bisexual or not, if they are in a monogamous relationship, it is very wrong to betray their significant other in that way.  If you want to work this out with him, I wish you the best.  If you want to kick his bottom to the curb...i'd be right there with you on that one! Either way I think you need to have a serious conversation.  You deserve to be treated better than that! Good luck

Ok - This has nothing to go with "testosterone or aspie obsession" hun. Either he is curious now or he has always been curious and you are just now finding out about it. I agree with everyone else... as much as it hurts... you are going to have to talk to him about it... It may be as simple as something missing in the relationship that he has felt too ashamed to talk to you about or too embarrassed to bring up. or maybe it's something that he is afraid that you would leave him over but regardless - honesty and openness is the only way to get this dealt with properly IMHO..

If he had suggested a three-some or broached the subject of polyamory that is a different matter to cheating.  Time for him to ask himself some hard questions I'd say. 

You have my sympathies , having been through a sinilar time.

Karen.