Is it normal that its been 3 years and he acts like its been 20

I would suggest trying to find out what's wrong without badgering him.

The last thing someone needs when they're not in the mood is being beaten up over it.

It could be male hormones, but it could also just be stress or worry. It could even be from a lack of sleep since you have a baby in the house.

Why don't you try finding out what's on his mind, listening to him to his needs and worries.

This is not normal behavior, he should first be checked out by a doctor, and cleared and then you both should seek couples counseling

That doesn't sound right to me. Maybe he has a psychological block based on your new role as a mother? Maybe it feels wrong on a level and sees MOTHER instead of LOVER. You being the mother of his child might relate you to his own mother in an unusual way? Just speculating. It definitely sounds like it's more complex than he's willing to get into. Sounds like he's just deflecting to end the subject quickly.

Could be that he wasn't ready to settle down, but you guys had a baby and he felt he had to? Maybe he is having doubts now that he feels like he has to stay with you? Again, just speculating.

See if you recognize any other behavioral flags... Such as frequent attitude, lack of care for things that are important to you, looking at other women, etc.

I didn't have sex with my EX until we had been together over a year(I wanted it, but I was a virgin and didn't rush it.) I thought once we did it we would have the rabbit sex everyone spoke of. We didn't. Actually, there was a period of time, only a few months after, where we didn't have sex for 2 months.

I felt ugly and undesirable. He would become erect upon laying against me and touching me, but once things turned more sexual he turned away and tried to sleep. Meanwhile I learned he was watching porn here and there instead. I'm a very attractive girl. I get hit on a lot. I get many compliments. I'm fit and have a great body naked(which I maintain).

Slowly I began to find he hates himself. He's VERY self-conscious. He is a case of "You need to love yourself before loving another". I tried to help him to get to a point were he felt good about himself, but he didn't have the drive to fix things he didn't like. I found this affected him in many areas of his life. He had a lot of emotional baggage to start. He never spent the time to accept himself. He lied to protect himself. Lied to seem like a different person than he was. He never laid to rest anything that happened in his life. Always lamenting. Very pessimistic. Every time something bad happened, everything came to the front like it was all laced together in a quilt of bad times to suffocate him. If I said one criticism, boom! Everything bad in his life suddenly lead up to that very moment. It was like the straw that broke the camel's back ALL THE TIME.

That was the underlying reason in my relationship that made him never want to have sex. No matter how often I reassured him and told him that his perspective was off. That insecurity and everything that stemmed from it was a big part of of why I couldn't be with him anymore.

Have you tried putting on something sexy? Maybe up your appearance and pretend you don't want to either, and see if he reacts. "Wanting what he can't have" ;) It can also help the labido if you're super loving and nice, a little goes a long way! Labido booster foods= Bananas, avacados! Also, if he starts exercising that can make a world of difference. Good luck!

Yes threaten to leave if it doesnt change. Thats what i did and now sex is more frequent.

Be very very sure you want to marry this man.

It sounds to me like it's only heading in one direction ... downhill towards divorce.

Anyway, do you really want to be anchored to someone who doesn't find you physically attractive any more? Was he there at the birth? A lot of men can't get past that vision of the baby being born.

Please postpone this wedding until both of you actually WANT to get married - not because it's expected.

How recently has he started to seem disinterested sexually?

That sucks ALOT - I've been with someone for around the same amount of time and we do not have this concern but I have had it with other relationships around this time. Again to talk about it is the only real way to deal but there are some reasons that you might want to check into:
Physical Attraction
Mental Attraction
Sex is boring, scheduled.....
you mentioned you have a kid - no privacy?
Porn addiction/habit

Sometimes I find that talking about it too much just makes things worse.... schedule a babysitter and get all sexified have a few drinks and just F* him like you want him really bad ~ if it doesnt happen after this effort........ then yeah discussion...... good luck - everyone needs to feel wanted.

He needs to see a doctor. Atleast, I think so. Either that or he's really stressed. However, sex helps relieve stress.

You should talk to him about it...

i find that to be a little un normal. the only way to clear up this situation is communication. as u stated u did things "backwards" but u have to understand tons of ppl do the same thing,its no excuse for him to not bring the fire. every woman wants to feel wanted and u need to tell him that. if this is how he acts now and just 3 years in, what behavior is he to exhibit in the future? gosh.

He's a closet gay guy and is using you as a cover.