Being an incoming partner in an already established relationship, there is something that might be forgotten in the drive towards feeling secure about your place within the relationship and that is intimacy, if you are in a comparatively new relationship with two (or more) partners who have had years to build up their intimacy levels over time, it is easy to lose perspective of this reality when faced with the evidence of this imbalance, it might easily get mixed up with general insecurity.
So what do I mean about intimacy?
Well firstly it isn’t about sex, another common mistake.
According to Wiki, ‘Intimacy, generally refers to the feeling of being in a close personal association and belonging together. It is a familiar and very close affective connection with another as a result of a bond that is formed through knowledge and experience of the other. Genuine intimacy in human relationships requires dialogue, transparency, vulnerability and reciprocity. As a verb "intimate" means "to state or make known".
In addition I would add that Intimacy is feeling free to be yourself 100% and the total safety and security in being accepted as yourself, warts and all. It is the lack of self consciousness that only comes in a long term relationship when you cease trying to keep up the pretence that you are flawless (and flawlessly beautiful) and amazingly hygienic without any effort at all…it is the intimacy of being able to be the occasionally spotty, farty, sicky, smelly selves. It is feeling comfortable enough to use the toilet in front of one another, not dying of embarrassment if you happen to have a bad evening of wind etc, these are not (unless you are unselfconscious to a fault) the kinds of things you feel totally comfortable with after a week, perhaps not even a few months or a year, but sometimes many years until you totally let your guard down.
You have to keep in mind that the intimacy level of your dyads are in the right place for the length of time of your relationships, if you were in a mono relationship you would not notice any difference, you shouldn't (though I appreciate that it is difficult not to) compare it to the dyads your partners have with each other, because the dyads you have are just fine the way they are and will develop at their own pace.
Intimacy takes time, it just does, you can’t rush it, though it can possibly be helped along by open and honest communication, you can’t possibly compare the intimacy levels between a relationship that is a year old, than one that is twenty years old.