I (21NB) have been dating my girlfriend for a little over a year now. I’ve been away in Germany for study abroad, and she’s been back in our college town. I miss her terribly, and our relationship has always been polyamorous but neither of us have really been seeing other people.

Is this your first experience with polyamory? Do you have previous experience being in a serious relationship with someone who is sleeping with and loving others? It can take practice to shed some monogamous programming.

I always thought I wouldn’t get jealous, that she’d still love me, etc. but lately I’ve been insecure because I don’t have a penis, and I feel like she’d like me better if I did

I think it is a bit unwise to make a story about how she thinks and feels.

Cut to about two weeks ago, when she tells me she’s been having sex with a new guy. At first, this hurt a little, because I felt like it wouldn’t have happened if I wasn’t in a foreign country.

Alright. Wait. You agreed from the start that relationship was polyamorous, but you didn't expect her to ever sleep with someone else and you think its only because she is out of town? If you wanted/want monogamy. Thats ok. Ask for it or find someone who wants it. But if a relationship is polyamory absolutely expect all your partners to fuck others. Its a given.

Then, she tells me offhandedly today that she got a second partner. This hurt me unexpectedly hard. It was different when she was just having sex, but to have an entirely new partner is really taking a toll on me. A lot of it is my own insecurities, but I really don’t know if I can continue this relationship with it still being poly. I’ve begun to realize I don’t want other people, just her. How do I convey this to her without her feeling trapped?

Ask for monogamy. Expect she will say no you and you will decide you arent compatible.