We got into swinging because the Mr. was interested in a 3some and the Mrs. was bi curious. 10 years later we have found swinging is mostly couples and one of us always feels left out. For the Mr., he doesn't like losing his wife in the midst of playing and for the Mrs., she doesn't enjoy watching the Mr. We are very much in love and we prefer being together in a 3 way connection.
What you are doing is commonly called Unicorn Hunting. Why Unicorn? [The you is generic here - not you specifically.] A unicorn is a hot bisexual babe who will happily have sex with both of you, love both of you equally, doesn't mind when you put the couple first in your priorities, is fine with having secondary status in the relationship, is fine with being closeted and just a 'close family friend' to outsiders, is ok if the couple has kids but is not allowed to have children fathered by your husband, doesn't need alone time with your husband or you, is fine with always having 3way sex, and so on. Basically, the unicorn gives all and expects little to nothing back. Of course, this creature doesn't exist - hence mythological and so ... unicorn.
Do a search here and you will find innumerable threads on it. Most of the threads will be negative - as in do not Unicorn Hunt.
There is nothing wrong with what you want. Lots and lots of people have the dream of finding a third person to be involved with both people in a couple. It's a lovely desire.
But there are a lot of common pitfalls that we see over and over here. And those pitfalls can cause enormous pain both for the couple and the women they date (unicorns are commonly bi women but not always).
One pitfall is wildly unrealistic expectations. It is hard to find one person you click with, no? Now you are seeking someone who will click with both of you, at the same level, throughout the relationship. That can happen but it is exceptionally rare. Most people click more with one person in a couple. Even if someone is wildly into both of you, that can change over time. Interests wane. Maybe one person in the couple becomes a friend type person rather than a lover type person. Or someone in the couple realizes they like the third person just fine but don't want to be romantically involved anymore. Change will happen. Setting hard and fast expectations before meeting anyone often just leads to disappointment.
Another common pitfall is being unprepared to deal with couple privilege. Search for couple privilege here. There are a number of good threads on it with different perspectives. Some examples of couple privilege is the expectation that the couple's desires and needs are put first, that their schedules are the ones to be worked around, that the third person is to be 'shared' by the couple, that they want to bring someone into 'their' marriage. This seems inherently natural to many - it's a common 'blind side' of our culture (assuming you are in N. America). But it can be deadly to healthy triads and lead to much pain for all concerned. (A triad is where all three people are all involved with each other.)
Specifically, if the Mr. doesn't like losing the attention of the Mrs. while she is with another person, and the Mrs. doesn't like watching the Mr. getting his freak on with another woman - why in the world would adding a third person help with that? You would still have the same insecurities and dislikes - but now you have a relationship with the person who is at the center (but not the cause as that is on you) of those dislikes and insecurities. Adding a relationship with the person will not solve those basic insecurities. It will make them infinitely worse because now there may be a romantic/love element.
And if the goal is hot threesome sex - and really nothing wrong with that! - there are infinitely easier ways to get that rather than seeking a relationship. Advertise on Craigslist. Get active on Fetlife if you are kinky. Find swingers who are specifically into MFF threesomes. They exist. Hire a pro. All of these are easier and less stressful than finding someone to love and have a relationship with and have hot threesome sex.
And if the goal is a relationship based on love and respect, what do you have to offer? Why should someone get involved with both of you? And what you can offer needs to be beyond sexual experience, dick or boob size, or financial stability. Why would someone want to date you? Why are you awesome? What's in it for them? Are you willing to do the hard work to be truly open to change your relationship and yourselves in order to become a healthy triad? It's a shit ton of work - a level of complexity beyond coupledom. It's not impossible - people do create triads. But it is quite hard.
And there are other pitfalls I don't mention here. I really strong suggest just browsing through the threads on unicorns, unicorn hunting, couple privilege and so on. It will be hard reading at times. You will say to yourselves 'But we are not like that!'. Do try to learn from other's fails. It may save you pain.
Our best experience has always been with a bisexual girl but that is very hard to find.
Yes indeed. See discussion of 'unicorn above.
We want to find an exclusive bisexual girlfriend instead of swinging...
Why? Is that to manage your insecurities? Why can't she date others outside of the couple? Why should she be exclusive to you? There is nothing wrong with wanting exclusivity. But know why you want it. Imposing exclusivity hardly ever works to manage jealousy, insecurities, emotional upsets.
We thought about gay clubs but worried that might attract the wrong type. We tried meeting single vanilla girls but that doesn't work.
'The wrong type?!' Do you mean actual lesbians? Or is the husband worried about getting hit by gay men? This reads dreadful but I am going to assume poor word choice. Most lesbians are unlikely to want to be involved with a male-female married couple. So, yes, gay clubs are unlikely to be helpful for you.
Do we try monogamous sites with girl looking for girl?
Goodness gracious no! You are not monogamous nor are you are offering a monogamous lesbian relationship. Ethical non-monogamy (poly and swinging are types of ethical non-monogamy) does limit the number of potential partners but it is really important to be honest and upfront about this. You are NOT a good match for anyone seeking a monogamous relationship. Don't pretend to be one.
Do we try dating separately and be honest until one of us finds a good match to bring home?
There is nothing wrong with dating separately. And some triads develop organically when one person in a couple dates someone outside the couple, and that person falls in love with the other partner. But it can't be planned for or expected. A good way to utterly kill any budding relationship with someone outside of the couple is to expect or require them to date/love/have sex with your spouse. Basically if you go the dating separately route, do not have the expectation that it will develop into a triad. Be prepared to deal with being either the 'hinge' of a V (where one person is involved with 2 other people but those people are not involved) or an 'arm' of a V (or both).
Are there any online websites with poly girls looking for couples
Polymatcher is one. I've not had good luck with them - limited number of people in my area. If you are kinky, Fetlife has ways to connect with your local BDSM community, many of which are poly or poly friendly. OKCupid is an option. There are ways to set up your profile to indicate that you are a couple and that you are seeking to date as a couple, or separately.