Help, I'm new to D/s and having problems in my marriage.?

Wife met a girl who rekindled my wife's love for being a sub. 7 years in marriage and It's new to me. I'm trying to learn and be supportive of my wife's needs so that I can be her Dom. Problem is she likes to play with the other girl without me. Makes me jealous and hurt. She won't give up playing with the othe girl without a degree of resentment twords me. She says she'll do what it takes to save the marriage but how long will it last. I said as long as we play together I'm ok. It bothers me that she has another ual partner and I don't nor do I want one. I just want my wife and whoever we can play with TOGETHER. We've been going back and forth on this with no resolution in sight. I told her I am doing the best I can to understand and deal with her wanting the other girl, but the jeoulousy and hurt resurrects itself. Need help from seasoned D/s people. Someone else must know my pain and had to deal with it. How did it end up for you? Did you learn to get over it?