lies!

So my boyfriend of 10 years has been caught in 2 different lies within the last 2weeks. Stupid little lies. But i feel like if he can lie to me about the small things. (Like where he got something. Or when he is planning to pick up hisnother kids.) how can I trust him.  The first lie I found out by looking at text messages from his ex! And the second lie his 12 year old son blew up the spot. I have confronted him on BOTH lies and he has still not admitted to the lies. I am feeling really lost. We have 3 children together and I'm 6 months with our 4th. I don't know what to do. I love him and I know he loves me.  I have never been the one to put up with bullshit or lies. I'm ready to leave. But don't really want to throw away 10 years. HELP! All advice welcome