Harsh words winterlace.
YABU/YANBU it depends entirely on the circumstances. When I got pregnant I think it was so unexpected that many of my friends thought they didn't really know me. For about 18 months before that I'd been through a very traumatic time, it changed me as a person and made me prioritise marriage and children very quickly. When I was pregnant I rarely saw my friends, but that could have been because of me, I lost my confidence a bit and none of my friends had been pregnant before so I felt very self conscious. They seemed to think it was just like shoving a football up your jumper and there was no effect on the rest of your body at all. I didn't even try to explain it wasn't like that because I didn't want to go on about being pregnant.
When my DS was born they all came to see him, I felt awkward around them but was pleased they were putting in the effort. After that things went wrong, I got seriously ill and couldn't see them. When I recovered I was so scared of getting ill again that I spent weeks just focusing on that and getting through each day with a newborn. They just didn't bother with me or DS after that.
DH and I rarely see our friends, they just don't like children and always assume we will bring DS with us. There is absolutely no reason for them to think this, DS has only seen them three times in 18 months - once when he was born, once when they came round before we went out for an evening with them and once when it was his christening. They didn't even acknowledge his first birthday. It's not that they think we have ignored them, they just assume that we will have changed so much that they no longer feel that they have things in common with us, and it really upsets me because I miss my pre-baby life a bit due to not being invited to anything with them anymore.
In other friendships I lost three friends (who didn't know each other) simply because they wanted children and found it difficult. I think the fact I got pregnant without much effort and without any warning to our friends was upsetting to them. I can understand this, but now I just feel unsupported and snubbed because after 18 months things are still off. When they get their babies I imagine I will be expected to be enthusiastic and pleasant. Of course, I will be, they will be fantastic mums and I would have loved to be close to them and their babies but I feel that too much has happened. How can I be so supportive when they resented me so much? I don't think those friendships will recover, maybe they'll realise that they were UR once they've had their babies and perhaps if they acknowledge the situation then it might be enough. We'll see.
OP, friendships change and some survive, others don't. I often feel lonely because of what has happened with my friendships, I wouldn't say that they have disintegrated because of me, but my changing circumstance was a contributing factor. Don't assume that just because you stay exactly the same then your friendships won't change/end because its often about how you are perceived. I didn't have the right friends either. It's terrible that the person having the baby is blamed for the friendships disintegrating, never mind that those friends should have been round supporting the new mum. It's a sign you're better off without them but I know this is difficult to comprehend. On the plus side, my friendships with people who have children seem stronger than ever, so I do agree with you on that point :).