I think I get it, but let me repeat it back so I know I'm on the right page here:
My wife and I met a woman. She wants to wait 3 mos before deciding if she can handle dating a couple simultaneously. I understand that.
While my wife and I both like her a lot, the woman is more into women than men. In the past when we hang out as a trio of new friends, I feel like a third wheel and left out. (I assume you guys are trying to hang out as friends here. Am I wrong? She is not actually dating your wife already right? )
How do I best handle my "third wheel" sorts of feelings here?
You could discern if you are being left out in actuality
or in your perceived reality.
If in actuality and they are doing "left out" behaviors toward you? You could ask your wife and the woman to include you in the conversation or activity so you can participate too. Whenever DH and I get engrossed in grown up talk that is boring (ex: dealing with paying bills) my kid is very clear when she pipes up.
"Excuse me. I do not understand what you are talking about. Could we change the topic to something I can participate in? I feel left out."
Which just slays me because... well. There it is! Crystal clear. Out of the mouth of babes -- and I wish more adults could be willing to just state it up front like that.
If it is in your "perceived reality" because they have a natural rapport and their friendship banter runs smoother/faster than your own natural pace? Like they are not leaving you out of the conversation or anything but you FEEL awkward or left out because your friend making skills are in another speed?
- You could work on your friend making skills.
- You could ask the woman to spend time with you alone, to deepen the friendship you and her.
- You could ask your wife if she could spend time with her alone to deepen the friend with her and new friend.
- AND you could spend time in trio learning how to work the overlapping friendships in that configuration when you are out together.
It takes time to learn the "new normal."
Could you be jealous? That the woman already has said she inclines toward romances with women than with men. So your wife, by virtue of being a woman, has a slightly better chance than you at a romantic relationship here? The woman could still say "No, I do not want to explore a triad thing with a couple at this time. But she could counteroffer with "I would prefer a "V" shape at this time with the wife as the hinge. Would you both be willing for that shape?"
You will have to deal with that possibility at that time. could read about jealousy
NOW though, to deal with your current feelings and consider what the future could bring or not. And talk to your wife if a "V" thing is something you both could participate willingly in or if that counteroffer would have to be a "no thanks, let's just be friends" or a "we will need 3 mos to think that over" or what. You are responsible for your own preparedness.
If other things are bothering you? You could elaborate here on what it is you feel or think about the situation and why you are feeling/thinking that. You could ask for feedback to help you discern if what you experience sounds like "actuality" things or "perceived reality" things.