Lexi, stop texting him, block his number, by replying you gave him the response he wanted. If you rent your home, contact your landlord and tell him/her that you do not feel secure in the home with windows that do not lock. In the mean time, go to Wal-mart, Menards, Home Depot, or Lowes and pick up some shims (ask if you don't know what they are, ask). Wedge the shim in the window to prevent it from being opened.

Contact the police immediately with the text messages, even though you don't have his info, get a PPO and call 911 if he EVER shows his face around your home again. I rarely support a person keeping their child from a parent not living with them, but risking your safety (AND that of your child's) is not a good idea. If he wants visitation, made him go through the court to get supervised visits.

Get your phone number changed immediately, do NOT give him your new number no matter what his excuses are. Don't give it out to anyone that would share that information with him. It's a good idea to get out of that social circle completely.