Well then I can see this has you a bit wound up.
So first caveat is they're your breasts. Who does what, when, where, and if with them. Is your decision beginning and end of discussion.
I can tell you this behavior is consistent with something described as adult breastfeeding. And it's something about 50% of married couples experiment with at least once, during the time that the woman is lactating due to pregnancy if I'm remembering the survey correctly.
Both genders seem to be fairly interested in it. And both cite the closeness and intimacy. The intrusive thoughts you've been having about it is like the number one thing for why women don't do it as far as I've gathered.
I want to highlight some of the things you said because they are kind of concerning.
Afterwards I ended up crying in his arms, filled with guilt
I can tell you this isn't an unusual reaction among those that practice certain kinks. Especially the first time.
I didn’t want to tell him anyway because he really liked it and I didn’t wanna ruin it for him.
I don't think that's all together uncommon. But you should flat out tell him. If my partner was practicing a kink they didn't like (unless not liking it is their kink I guess) just to make me happy. I would be mortified, and it would make me feel like a borderline predator.
He even said he started sucking on his finger because of how badly he wanted to do it again, and that comment was where I lost it.
That is super concerning and extremely manipulative and immature. I would never try to manipulate my partner into trying to do something they don't want to by telling them how much I enjoy it.
I think I got the ick because he’s acting like a baby, but he’s my boyfriend and I don’t want to date a guy with behavioral traits of a little kid, especially after the breastfeeding thing.
I think everybody has things in the bedroom they like that doesn't necessarily reflect them in the rest of their life. But it's completely okay for you to not be comfortable with that you don't owe him a relationship.
I ended up telling him about the intrusive thought. He apologized profusely and assured me he saw me as his girlfriend, not his mom.
Excellent that's the kind of reaction a supportive partner should have to pushing your outside your comfort zone.
But he said I ruined it for him, and he is beyond devastated he won’t be doing it again, or anytime soon.
Not so excellent. There's that immaturity and manipulation again.
I just want to know if the finger sucking thing is normal
I don't think most men of sexual maturity are self soothing by sucking their finger no, I can say that pretty confidently.
or if any of this is normal.
Everybody's different when it comes to sexual proclivities what's more important is how you feel. If it makes you feel bad and guilty it shouldn't be done simple as.