<human>: My [28 F] boyfriend [30 M] of several months is going to spend the upcoming long weekend (3 days) travelling with his ex-girlfriend [30 F]. I'm feeling somewhat uneasy about it.

He told me about his plans less than a week before the trip when all travel arrangements had already been made. He started the news with "I know this may disappoint you". It's just for two of them, no other friends are going join. He admitted that they might share a bed in hotels. He said that I shouldn't worry about it.

I told my boyfriend that it's not okay and I'm feeling uncomfortable. He said "I'm sorry that it makes you sad" and didn't do anything to change it.

One important detail is that my boyfriends's ex doesn't know he is in relationship with me or in any relationship at all now. My boyfriends told me that he broke up with his ex and I shouldn't worry about it because they are not a "couple", that they are just very friendly. By the way, they don't have kids or any financial issues that might hold them together.

I'm usually very happy when I'm around him. I'm not a person who makes scenes or starts fights. Being next to him makes me happy enough that it becomes impossible to be visibly upset even if I something is very disappointing to me. It seems like I can't express my negative emotions properly.

Thinking about my boyfriend planning a vacation secretly and sleeping in the same bed with someone who thinks he is single gives me a sick feeling. I couldn't sleep well after I found out about his plans.

What should I do? How to cope with my emotions during this weekend? It hurts. I don't want to turn into a crazy-jealous person and ruin a good relationship.

Can you condense the text into a few key points?
<bot>: My boyfriend is going to spend a weekend with his ex. I'm feeling uneasy and don't know what to do.