Issue with partner. AIBU by feeling upset about this...?

[BehindBlueEyes26]

So, to keep a very long (and pretty horrendously crap) story short...
I'd graduated from uni and only just moved in with my then boyfriend (now fiancé) when I found out that I was pregnant. It was a really tumultuous time, which we somehow managed to survive. It wasn't the right time for us and he was very clear on that. I knew he was right and I did agree, but I always found him reluctant to get emotional about the subject. He was pretty firm in his feelings that it wasn't the best time. Never nasty, but almost a bit cold in a way. Probably just because he didn't want to get upset about it. Anyway, I had an abortion and even though years have gone by, I still feel haunted by it. While I know it was definitely the most sensible decision and I was very young, it still hurts a lot.
Fast forward to now, and my partners young sister (she's 17) has just told us she's pregnant. She hasn't finished college, still lives with his mum and dad, and is (if I'm being honest) still in the throws of being a full-on teenager - doesn't like being woken up in the morning, doesn't know much about looking after herself, bit self-indulgent as most 17 year-olds are... He is being very supportive of her. To the extent where he wants to buy her baby stuff, has been excitedly talking about baby names and more.
AIBU to feel really envious of this? I know, I really do know, that it's different but it really stings to see his enthusiasm on this. His sister is possibly in an even worse position than we were and it irks me when he excitedly talks to her about it. I know I sound awful :( so that probably already answers my question. But I almost want to ask him why couldn't he have been even half as enthusiastic for us, if that makes sense?

He's older, has more perspective. Completely different being a big brother to sister having a baby than having your own baby. His life won't chage that much if at all with his sisters baby

I think that's a natural reaction, especially as you appear to be still grieving for your unborn child. Have you received counselling to help,you through this?

Have you got any children now?

I guess your partner has forgotten how young and insecure he felt when you were pregnant?

I think maybe you need a calm discussion with your partner about how the sister's pregnancy is making you feel, his reaction past and present etc.

He is being very insensitive. You are probably always going to resent him though so not sure there is a way forward.

Maybe he's being a hypocrite, in which case you have every right to be totally enraged with him. However another interpretation could be that he too has regrets about the abortion. It could be the second. I think you need to have a conversation about it.

I hope it's the second. I wouldn't be able to plan a future with a man who was capable of doing the first.

I think it's totally different when it's not your child.

YANBU but equally neither is he.

I think he does feel bad about it, we've had conversations where he's say as much but honestly, it's been like pulling teeth trying to get anything out of him! His general demeanor when something upsets him is to clam up and I know that. We don't have kids at the moment but we're planning on starting to try a few months or so before we get married. So I know it's in the pipeline, and actually he's been the driving force behind us deciding that. I just feel like he's being insensitive and I don't know the best way to bring it up without sounding like I'm being bitter.
He's a planner by nature, and I know I shouldn't take it personally, it's his sister, not him. But it does hurt.

I would see this as him being a supportive brother. I am assuming his sister has decided to continue the pregnancy so that's the decision and everyone hair has to accept it. Far better to get enthusiastic about it than keep on saying she is too young etc. You made your decision and she made hers. He didn't make her decision, he's just being supportive about the one she has made.

I would go for counselling to think about what you actually want, before going down the route of babies and marriage with him.

It seems that he is calling all the shots and making the decisions and leaving you resentful. Better to think about this now. It should be what you both want together.