You're not alone, I promise. You're not even alone in feeling alone: we've had tons of users over the years come in feeling similarly, sure it's only them. It's not. It's never been. It's not only you, either, not in any part of this.
I ideally never want anyone to feel ashamed of anything, but if I didn't have that view, I'd be saying that the people who *should* be ashamed here is anyone saying anyone has to "learn to like" any kind of sex. I'm mortified at those kinds of notions and even more so at someone telling someone that. I also have a very pointed stink eye happening right now when it comes to what your therapist said (here's hoping they don't have any LGBTQA patients, FFS).
To be consensual, sex has to be optional. We all need to be able to only engage in the kind of sex we really want to, which, go figure, almost always tends to be the sex we really like. Suggesting someone needs to have a kind of sex they don't like is not only profoundly sexually unenlightened, it's just a really gross thing to say. Mind, it may be some of the people saying that to you are themselves having sex they think they are obligated to have and that they really don't want to, in which case the way they have been talking to you is not only awful to you, but really sad for them.
Other forms of sex *are* accepted and validated. Clearly, not in the circles you've been running in and talking to about this (and whooboy, IMHO, does your therapist need some training and education when it comes to talking to patients about sexuality), which stinks, but the good news is that that's not representative of the whole world. For sure, as a whole world and all its cultures, we still have a long way to go when it comes to presenting sex as for mutual benefit and pleasure (not for only the benefit of men, with everyone else just doing a duty), to recognizing sex as something people have always primarily done for pleasure, not procreation, when it's been a real choice, and to real, full inclusion for everyone, including people who aren't straight, and including people whose sexualities and sexual lives don't fit the strict and restrictive lines of heteronormativity (in which intercourse reigns supreme, as you've experienced).
I personally haaaaaaaaate the word "penetration" (it sounds like a description of rape to me, not like consensual intercourse), so you will often not find it in our content, but if you take a spin with the search function on our main site, you'll find at least a few advice columns and articles addressing the reality that there are plenty of people who don't like or want to have intercourse, or who like it fine, but who don't get off from it (hint: the majority of cisgender women don't, period) or for whom it just isn't a favorite thing. I think seeing some of those pieces might help you to feel less isolated. This one --
http://www.scarleteen.com/article/advic ... ntercourse -- and this one --
The Great No-Orgasm-from-Intercourse Conundrum -- might be good places to start.
How do you feel about changing up or expanding who you talk to about sex? Personally, I'd stop talking about any of this to anyone who says or suggests that something is wrong with you for not liking one kind of sex, and, worse still suggests you should have to engage in sex you don't want or like. I'd also personally seriously reconsider seeing a therapist who said what yours did unless I was otherwise very much benefitting from working with them (in which case maybe I'd stick around, but I'd also want to say something about what they said, make clear it wasn't okay or very informed, and ask that we not talk about sex in our therapy again until they got some more current and inclusive education).
If it helps, know you found a place where we all know full well how incredibly diverse sexualities and sexual lives are, how much what everyone does and doesn't like varies, and where we've worked hard for almost two decades to make the reality of sexuality -- very much including this kind of diversity -- clear to everyone. In other words, we've got your back around this, for sure, and if you want to at least add one community to your life where you know your sexuality and the sexual life you want is supported, you found one.
Happy to keep talking from here however you'd like. Let's see what we can do to help you get rid of any residual yuck from some of these other messed-up messages and get closer to claiming your own sexuality as yours, feeling confident and happy about what it is you want and enjoy, with no need to do anything you don't.