I have my husband, who is my primary. I also have my "other husband." I also have a steady boyfriend. We also swing. So, I have several men that I see either regularly or on occasion. My husband will always be my primary. I love my husband and my "other husband" equally. The love I feel for my boyfriend is right up there as well.
If you fear that you may lose your status as her primary man, you need to express those fears to her. Let her know that you are more than okay with her seeing this other man, but you want to be reassured that you will not lose your place with her.
Do you feel that there is something lacking in your relationship with her? If so, that needs to be addressed. If you feel that your relationship is solid, then you have nothing to fear.
If you two have been swingers, and it turns you on to see her with other men, why is it not a turn on knowing that she may have found someone that she really likes?
My husband is very compersive. He actually feels most loved when I have sex with other men. And the relationship I have with my "other husband" is very solid. I have known my husband for 7 years. I have known my "other husband" for almost 26 years. I have a lot of history with my "other husband." My husband could be jealous and fear that he could lose his place in my heart and in my life, but he knows that will never happen. He also knows that my relationship with my "other husband" is just as solid as my relationship is with my husband. They are on an equal playing field.
If you fear you may lose your place, you have to ask yourself where you may be lacking and how you might make your place more solid.
You can PM me if you like as well.
Debbie