Truthfully, this is the time he probably SHOULD be putting those extra hours into starting a band - the baby isn't born yet. Once the baby is born you'll want him around even more.
Like I said I'd never ask or tell him to quit I love what he does and support him all the way.
I would allow him to have his hobbies just make sure to spend time at home with you too. Remember, when this baby comes you will probably want him to take some time off to be home with you. You may be so sleep deprived that you cry. Guys really do need to have hobbies and taking them away can cause them to feel controlled and they will start to resent you. Hobbies are great in moderation. And here is a little secret, most young men I knew who were in bands all quit after they started having babies. Support him now, he will be so greatful, then once baby is here he may feel that it's more important to be home a lot more.
My husband is a drummer. When we found out we were having our first we talked about it. I told him I didn't get married to be alone. So I want to go with you if I can. He agreed and also said he didn't want to be in a big touring band he just wanted to play his drums. I love watching him play and so do our children. We even talked about if he did tour us going with him. He still plays but hasn't been in a band in years as he can't find anyone who wants to just keep it as a hobby so he plays for us :-)
I'm not telling him not to I just love him bring home with me especially when morning sickness kicks in. I love him playing music but I also love when we are together... I think I'm just being a hormonal ***** idk I know he'd never cheat on me
Make some agreements if you can about when he is free to book his time. If the money is good, it's certainly worth it. Is the problem that he's gone or is the problem that you think he's acting like a single guy? If the latter, talk to him about that directly rather than whining that you're lonely and trying to control his actions without saying what you suspect. Seeming generically needy (even if it is driven by legit fears that he's not just playing the guitar but is playing around) just makes you seem less attractive. I'd be delighted if my husband took a gig to earn us more money when I was pregs, but would not be delighted if it actually was a signal of him wanting to get away and cat around and be free of me. Then it would be time to talk about that.
My husband is a DJ. We are expecting our second. While pregnant with our first I was out every Friday night with him but this time I've only made it out maybe twice since September. It's a secondary source of income and it's an excellent way for him to get social interaction outside of work and home. I miss him, our son misses him, but I'm not going to tell him he needs to stop - he's slowed down and doesn't book himself every week anymore, but that's his own choice not mine. I knew he loved to do it when I met him. I don't get to choose when and if he stops. He stays home with the kiddo when there's something I want to go out and do, too - he's not the only one who gets to go out and have fun.