I'd still rather maintain my autonomy by making the best decision I could in the circumstances. I don't know this woman's situation, so I can only give hypothetical opinion. If I were pregnant, wanted to terminate, and had a DP that was going to insist I continue the pregnancy, or end the relationship, or maybe even be pressured into something I didn't want to do, I'd consider just doing what was right for me and not telling my partner.
But I have been in an abusive relationship, and have pretty extreme illness through pregnancy that would impact on my ability to work or care for existing DC, and would impact my physical and mental health in a big way during and after pregnancy. Not saying that OP is in these circumstances, but I could definitely do it if I were. I don't think that makes me despicable and to be honest, if other people did, I wouldn't care anyway as they don't have to live my life.
Of course if I were in a relationship where I might face emotional blackmail or threats to leave if I were to consider a termination, I would probably leave it as I'd feel better off out of it anyway.
OP is in a difficult situation, anything she does is going to be difficult for someone, whether she goes ahead, or follows advice to talk to her partner, or feels pressured to continue the pregnancy. I think it's kinder to be understanding here, and save the opinion for some other time when there isn't another person in a highly emotive situation, with hard decisions to make. I know it's AIBU, but a bit of self moderation wouldn't go amiss, sometimes people post in the wrong place and just need support, not opinion, anyway.