Relationship Matter: I Feel Insecure in My Marriage

I’M ABOUT TO BLOW UP ON MY HUDBAND

I’m about to blow up on my husband and I’m honestly not sure if it’s just because of the situation or if it’s because I’m pregnant and full of hormones.
Some context, his friend decided to cheat on his wife and his friend’s wife has relied heavily on my husband for everything since they split up. Not only that, my brother in law is depending on my husband too.
Now, my husband frequently states he does not like this woman whatsoever in any form. But out of kindness, he is still supporting her. This is really affecting my hubby’s paycheck for all of us (me, my husband, my brother in law and our first child).

She has a lot of fancy tools and keeps bribing my husband and brother in law with free furniture and electronics for helping her. Now this alone I don’t have an issue with, it’s fairly fair trade for everyone.
The issue comes in with the fact that she is constantly asking my husband and brother in law to go out
drinking, amusement parks, to the movies or other places. Fully knowing that the things she is asking them to go do, I can’t join and even if I could, she knows we have no one to babysit our child; she has her soon to be ex-husband to watch over her son on demand.

When they go out, no one ever invites me; or mention me at all.

Currently, she is talking to my husband over a video game chat. This honestly pushed me over the edge as she has been begging to play with them over weeks and they said that they kept blowing her off because they don’t want to play with her.

All of these along with the fact that my husband has not been telling me about when she messages him at all lately. My brother in law has told me several times about when she is talking to my husband and he hasn’t told me. Like even when he’s at work or late at night when she should be sleeping. Is just too much for me to handle and not think is
sketchy.

Since being with my husband (four years) I’ve not for once felt insecure or worried about his commitment, until now. We don’t ever dictate or control who the other talks to or doesn’t (this is because, this is a committed monogamous marriage). We don’t look through each other phones or really do anything to make the other uncomfortable. I’m not sure if maybe all the stress is getting to him or if I’m not just doing enough for him. Maybe I’m just being hormonal. Thought!

What can I do to save my marriage?