I (F, 23) am dating a (F, 22) and we've been dating for 10 months. So far the relationship has been amazing and definitely the most healthy and stable one I have had. I suffer from BPD (borderline personality disorder) and have been trying with all my might to work on my issues because I want this person to stay in my life for the long haul. I'm getting very good at communicating and regulating my emotions and she is very supportive of me. Even though I'm getting better at recognizing when an issue is an actual issue or when it's just my BPD taking over my mind, it's hard to decipher when a line is actually crossed sometimes. The current issue I'm dealing with has to do with her best friend. Her and her best friend are extremely close and have been for about 10 years. We will call her Megan. Megan is an absolutely wonderful and loyal friend to my girlfriend. Despite this issue I'm having I actually adore Megan as I find her hilarious, interesting, kind, thoughtful and fun to be around. However sometimes I feel like the relationship between Megan and my girlfriend is maybe crossing some lines. I believe (or am hoping) they are most likely very innocent and not intended in the way I'm perceiving however I can't help but draw certain conclusions from things I've seen.
Megan does things like buy my girlfriend expensive things that she can't afford. Things like some sweatshirt or clothing item she really wanted, or concert tickets to her favorite bands, so on and so forth. She's promised my girlfriend to one day help pay for a surgery my girlfriend has always wanted. I unfortunately can't afford to drop a lot of money on my girlfriend so in that aspect it makes me feel as if I'm not really measuring up. That alone wouldn't actually bother me at all, at the end of the day I'm honestly just happy to see a smile on my girlfriend's face regardless of who is responsible. What bothers me the most is that they both (more so Megan) have a this "joke" about how they are in a relationship and call each other girlfriend. They will post pictures on social media jokingly calling each other "lovers" or "in a relationship" or "getting married" or "soul mates". The other week Megan posted a photo of them holding a baby and kissing the baby, joking about how they finally adopted a baby into their "family". When I see things like that, it makes me feel incredibly left out and sort of disregarded. When you go on Megan's instagram, it's nothing but her and my girlfriend and photos of them posing in romantic ways with romantic captions. To them it's been this years long joke between them, but I can't help but take it somewhat seriously. What's worse is that when I hang out with the two of them, I'm entirely ignored. I feel like I am the third wheel as soon as Megan is around. They have extremely similar personalities, like all the same music and have way more common interests than my girlfriend and I do. My girlfriend also once told me that Megan was her first sexual experience, although it was only when they were very young and drunk and stupidly decided to try lesbian stuff. Megan is also just now finding out that she is into women as well, after dumping her boyfriend. The combination of all of these things are bringing about quite of bit of insecurity in me. I calmly brought it up to my girlfriend, but she laughed it off saying they're like sisters and it's nothing to worry about. I believe my girlfriend as I definitely don't think she feels anything for Megan more than a friend, but I get slightly possessive vibes from Megan. I've also seen Megan drunkenly send things to my girlfriend paragraphs about how she loves her more than a friend, more than a sister, more than anyone she's ever loved. I suppose I just need help trying to sort my emotions out and decide whether or not this is something anyone would be upset with, or if I'm being overly sensitive. Any advice or opinions on the situation? Thank you :)