Have you ever had sex without kissing the Woman you were with? See, kissing is mostly a sign of
passion, not necessarily a sign of love. And passion is a great part of what helps build up the erotic tension and energy that provides for
arousal which then leads to a great(er) sexual experience. An
open mind seeded with
arousal opens up the body to give and receive pleasure; passion feeds and intensifies that pleasure and leads to real
satisfactory fulfillment.
If you want for your Woman to experience the sexual fulfillment she, as your Woman, naturally deserves - including perhaps a climax, a squirting orgasm or, even better, multiple orgasms, leg- or bodyshaking orgasms, or even deep body-filling orgasms - then you cannot legitimately keep her from kissing the man who makes her sexual match! BTW kissing will be induced and come naturally when there is mutual attraction between her and him.
You better sit back and just enjoy the show instead of being a crank and ruining a good thing and - with the right guy - for her probably the best thing that could imaginably happen.
You as her primary boyfriend should empower her not keep her down, don't you think? Besides a hint of jealousy is one of the essential ingredients of the emotional turmoil which feeds the cuck's mind and desire and is a relevant paving stone of the path to
your sexual gratification. Think of it.