There seems to be a lot of emotional undercurrent going on with Sarah (and you, but you know about that
). A lot of people keep things inside for years for many different reasons. Sometimes they feel if they just push it all down, it will go away, and they don't want to deal with it; sometimes it's fear; sometimes it's that their feelings go against the life they think they should have. It's endless, really.
The only way you're going to know what's really going on with Sarah, and why it's been kept inside so long, is to ask her. So counseling sounds like exactly what the two of you need right now. I'm glad you found somebody who is knowledgeable about these types of relationships. That makes a big difference.
Something I've learned (in my schooling to become a counselor, but in my private life, as well) is that there is an interesting process that happens with love and relationships that is just as much physiological as mental and emotional. Around here it's called NRE. Basically, when you are attracted to somebody, your body releases a ton of chemicals -- serotonin, dopamine and others-- which make you feel GOOD beyond belief. The purpose of these chemicals is to bond you with a mate and keep you there, at least long enough to procreate and have a baby. These chemicals generally taper off after about 18 months. Another chemical is still released (oxytocin) which keeps you bonded after that.
The reason some of the chemicals dissipate after 18 months or so is that they are so powerful that you wouldn't be able to function properly in life if they stayed forever! But the downside is that these chemicals-- which activate the same part of the brain as drugs like heroin-- can also affect your judgment and impulse control. So basically you see the person you're into through "seratonin-tinted glasses." Their faults are not noticed, or seem like no big deal, their positives are accentuated, etc.
And when the drugs wear off, that's when you really see if what you have is a strong bond, or not. This is the point where love actually happens, when you start to see the person as they REALLY are, and choose to love them. It's also where the work comes in, with needing to communicate about issues and work through them.
People can make really bad decisions in the midst of this NRE stage, which is why around here they say wait at LEAST a year, maybe more, before making big decisions like moving across country, moving in, etc. Another side effect is that their focus can be so on the person that they're having these feelings for that they literally ignore the other people or responsibilities in their lives. Lastly, people can get addicted to that feeling, and start flitting here and there to get that rush, that high.
So maybe a question you want to ask in counseling would be if Sarah could see waiting, say six months, and allowing the two of you to work through things in counseling, to build your foundations, to work on yourselves independently so that you can bring your best selves to the relationship. I would think that's not a lot of time for her to be on pause, but enough time to really take a good deep breath, clear the air of the NRE, come down to earth and take care of each other for a little bit.
It might also give you some time to look at where your insecurities are coming from, and work through them in counseling, where you can have help in expressing those concerns and seeing what the things are you need to work on for yourself, and what might be the concerns you can work on with Sarah (e.g., needing more hugs and reassurances when she's in the throes of NRE).
The concern in the back of my mind is that she may be becoming addicted to that NRE feeling, the serotonin and dopamine high. Maybe she wants to do swinging, where she feels that high and runs with it, until she doesn't, and then finds somebody else who provides it, with no feelings or actual relationships getting in the way. Chasing that high could definitely impact your relationship (and her own life) if not done with care, caution and consideration.
This, of course, is just a possibility, but something that could be discussed more deeply with a professional.
