Desperately need help.

I'm 5 months pregnant with our second baby and we have a 10 month old. We've only been married for 1 year and 4 months. Below are reasons why I think he might be hiding something from me and I'm not sure what to do. I've asked him once he said he's not but understands why I think that - no attempt to make me feel secure. I love him so much and I'm scared that my crazy hormones are just making me paranoid or it my gut is right? If I keep asking I'll ruin the marriage, if I keep thinking it over I'll ruin the marriage and if he was hiding something and I told myself I'm just overthinking it, that would destroy me.

1) Started to become distant

2) always on the phone

3) changed password randomly - I asked why he said for security reasons felt like he had the same password for awhile. I asked to text his sister my phone was dead instead of just telling me the password he insisted in unlocking it.

4) what happened in the past (8 months ago)- use to send sexual images/sext with a married women before we got together but stayed in contact even once we got married but no evidence of him cheating - he apologised got extremely upset and didn't realise the extent of the harm he had caused until I nearly left.

5) changed views on marriage - use to have similar views - fight to make it work now he concluded people end for a reason which is okay

6) I couldn't sleep one night just kept thinking of him cheating. I told him I had a bad dream I was scared to accuse him because he told me his ex accused him and he hated his ex ect. But he just came out with it, he asked if I was worried about him having an affair. I said I think so but I know how silly it sounds ect he said he's not but understands and gets why I think the way I do - he said I mentioned how distant he was being and with what happened in the past he gets why I might think that - didn't offer an explanation to why the distance? - Didn't bring up the conversation again - avoiding? Didn't try to secure me in anyway.

7) last time a compliment was mentioned was Halloween reveal party - use to always give compliments

8) made no effort to resolve the issue of me thinking how distant he's been

9) Having to stay extra hours at work after doing 12 hours ( this is the first time tonight) - even though saturday I asked how work was he said so quiet he didn't know what to do with himself now he messaged me saying his manager asked him to work a couple of extra hours tonight? (He's a senior career)

10) pointing out that it's okay to flirt with other people.

I'm sorry it's a long post I need advice I don't have many friends to turn to and I just don't know what I should do?

***Note I have a 10 month old son who is in bed by 7pm (he doesn't finish work normally till 8pm) I can't follow him as I wouldn't be able to leave my son at home alone, nobody lives near to watch him and I don't fancy disturbing my son's sleeping routine just incase he was hiding something