Hi, I’m (m20) and have been in a relationship with my girlfriend (f21) for 3 years. She has a best friend whom she’s known for 10 years. The thing is, she doesn’t really have any other friends because most people have distanced themselves from her. She goes to evening school and has classes on the weekends. During the week, she doesn’t do much and is always at home (though she’s currently looking for a job). She’s also had severe issues with depression for a long time and was even hospitalized once after a suicide attempt.

Now, I’ve always felt pretty insecure about her best friend. She’s assured me that nothing has ever happened between them in those 10 years, but to me, I just don’t believe in male-female friendships like that. I’ve made that clear to her many times. A few months ago, she spoke to him and told him she’d be seeing him less in order to avoid hurting me. I really appreciated and respected that. Lately, I’ve been very busy with work, and we don’t see each other as often—mostly only on weekends. She’s told me several times that she feels lonely at home and wishes we could go out more, but I’ve got a lot on my plate and have to work to pay off some debts. I also need to be there for my family, since my mom has become ill.

Then yesterday, she broke my trust. I was going to pick her up for the gym, since we haven’t gone in a while, and suddenly I saw her riding an e-scooter with her best friend. I was completely shocked. She then told me that in the past four months, he had only come by twice briefly—once to drop something off, and this time to pick it up—and that they hadn’t otherwise met up. She claimed it was just a one-time thing. It broke my heart to find out this way, especially because she kept it from me. She said she didn’t tell me because she didn’t want me to overthink, since nothing happened. But I’m terrified that he might try something with her, or that they’re having an affair and playing me. She told me again that she feels incredibly lonely and has nothing to do all day, and that it’s really getting to her. She just wants to spend more time doing things with me. But she doesn’t seem to understand that I can’t be with her every day!

This situation with her friend has shattered me, especially seeing them like that on the scooter. Honestly, I don’t believe her that he’s only come by twice. Now her mother has talked to me, too (she brought up that my girlfriend barely does anything and she’s worried it’s making her depression worse). Her mom said she wishes I’d go out more with her daughter. But how? I have no money and barely any time—we simply can’t have frequent dates. Her mom also supports this friendship and told me she’s had a male best friend for decades and nothing ever happened. But that doesn’t make me feel better.

I never forbid my girlfriend from seeing him, but she knew very well how much it bothered me, which is why she cut back on the contact. But this? This just feels like betrayal. I’ve lost my trust in her and don’t know what the right thing to do is anymore.

AITAH?