How can I (32/F) deal with feelings of jealousy?

How can I (32/F) deal with feelings of jealousy?

I feel very uncomfortable today. My partner (34/M) has friendships with women, two women to be exact.

Our relationship is two years long.

I don't know either of them personally. I feel so jealous. Today he's meeting up with a female friend (34/F) ; they're going to the movies, and I'm never asked if I want to come along. He said I can come next time they meet; he'll ask her if it's okay. Why he needs to ask her if its okay that i will join them next time?? How can I deal with this jealousy? I could burst with jealousy; it's very stressful, especially since I feel so excluded.

TL;DR: My Partner (34/M) doenst includes me to his female friendships. My jealousy is eating me up inside. its causing me a lot of stress.