Don't worry, would you be so concerned if he was seeing a girl? Your sons ADHD and possible aspergers will complicate matters, but no more so than if he was in a hetrosexual relationship.
DS is nearly 14 and came out as pansexual (I think he uses it as a less mainstream and cooler term for being bi). He hasn't had a real boyfriend or girlfriend yet though. I can't see myself worrying about him having a boyfriend if that happens.
Like other posters have said, being safe and looking out for red flags s what matters, but remember that a girlfriend can be abusive too. DB's XP was emotionally abusive and physically violent. Keep talking to him, you sound as though you're doing a great job.
One of the biggest problems for young people who come out as bisexual is parents' attitudes. It's really good that your DS feels he can talk to you I wouldn't worry about it now - focus on making sure he knows how to read social cues and safe safe.
I think this website has some good advice:
How can parents begin to think about this issue?
Be concrete (talk about the penis or vagina, not the birds and bees) Be consistent and repetitive about sexual safety Be sure to address the social dimension of sexuality Find someone of the same gender to teach the basics of safety and hygiene Redirect inappropriate behaviors. For example, if a child is likely to masturbate in class or in public, give him something to carry or hold, etc. Strongly reinforce for all appropriate behavior Think ahead - be proactive ("pre-teach") ( www.myaspergerschild.com/2010/10/aspergers-teens-and-sexual-issues.html )
however he's talking to you and it sound like he's being honest which is bril. I think the " searching on line" is the most scary thing coupled with his ADHD /aspergers and that lack of impulse control and the relative inability to read social situations that goes with that.
There are many lesbian/gay/bi phone help lines that could be useful rather than an un vetted " random" on the web- has he tried that? Google for your local one.
Ultimately the most important thing from a pragmatic point of view is staying safe, yes using condoms in what ever encounter, but more than that, for every teen choosing safe people to be in a relationship with and avoiding all those relationship red flags that we read so much about on mums net. I guess choosing safe people to have relationships with and behaving in a " safe" way yourself if you are on the spectrum is really difficult (not to say being on the spectrum makes you unsafe but I think you find it much more difficult to work out why being controlling might not be a good thing etc .... eg family money needs sorting I will sort it and you don't need to have anything to do with it. See I have paid the bills/rent etc all is well... have £5 pocket money , could be an aspergers response to finance but it might not be appropriate)
Hope I'm not speaking out of turn and am probably over simplifying things...
It came out because he texted a friend of mine (without realising who it was) on Quickchat yesterday and asked him what his sexuality was. My friend showed me the texts, as he was very concerned. It all came out last night, he says he has been seeing a boy for a few months now (when he told me it was a girl), and that it is finished now. He was searching online for someone who might be Bi also so that he could talk to them about how he feels.... He has ADHD and unconfirmed signs of Aspergers, and I am worried silly about him and this reckless behaviour. He says he was not trawling for sex, and swears that he has never actually had sex, just really felt comfortable with this boy and was happy being with him. I have said I will find someone he can talk to, but really I haven't a clue where to go or what to say next...