I have a relationship that has been developing for about a year. Dating for about 7-8 of those months. Everything was great, but I took a vacation to Japan, a life dream of mine. The gf is extremely jealous and my trip is for 6 weeks. I message her, or she messages me, on a daily or at least every other day to check up. A little over 1 week in she messages me that she can't handle the jealousy and wants to break up, so I tell her if that is what she wants and that's the end of it. Two days later she messages me asking if I really wanted to be with her and I said yes. She messaged back that she was so glad because she was so in love with me.
It is currently over 3 weeks and she messaged me again telling me that she was mad at me and that she didn't have a reason, it was just stuff in her head. She asked why I even got with her if I was just going to leave her for so long, especially for a place where I find the women attractive. I tried telling her that it wasn't the plan and that I haven't had any desire to do anything with the women over here, which is true. She called me a liar and said that she didn't want to be with me anymore. Once again, I told her if that's what she wants.
Hopefully, this still fits the criteria. It's a little muddy. Any tips on maintaining trust across so much distance or other ways of handling situations like this? I have never cheated on anyone and have never given her a reason to believe that. However, she has had several issues with her exs. Any advice is appreciated. Thank you.

RED FLAG.
You handled it well.

Sounds like this woman is going to make your life miserable in the future over jealousy issues. One small look to that attractive a girl passing by, one small smile to the cute waitress and all hell will break loose.

Who the heck gives an argument "why you got in relationship with me if you were going away for so long (6 weeks, which is not really too long considering 7-8 months of dating".
- A very insecure person who bases her happiness on another person.
- An incomplete person who is not in harmony with him / herself.
- A woman who is afraid to be single. Someone who wants you to spend every possible moment together, suffocating you with constant attention.

Look at her history and see if you can identify some of the above.

There are couples who are separated for months due to working in different continents but they are secure about their relationship with each other. Evaluate your relationship with this woman and if you are considering something serious down the line then think about her behaviour during arguments and how she handles difficult situations in life. Overly jealous poeple do not make good partners because of deeper insecurities within.

Sounds like a real whack job.