Once upon a time I'd have said, "Trust your gut, Thulas", nowadays, I say, "Trust your first instinct, Thulas". You felt, and seem to still feel good about a four month separation. Have your feelings changed?
In four months time, you will see if he's come up with the money for, and has seen a therapist. In four months time, you may have the opportunity to attend some counseling sessions together to work on marital issues before reuniting. In four months time, you may have a clearer vision for yourself and for the situation so that you can draft a "reunion agreement" to help guide your marriage back on the right track once you're under the same roof again.*
Whatever you decide, do it because it's what YOU want. Honor yourself first. Ask yourself which option might you most likely regret: sticking with the four month separation, or cutting it short. Weigh the pros and cons. You will make the best decision for yourself!!!
(A reunion agreement is one that you both agree to follow, and might include things like "no porn", "no missing counseling appointments", "no discussion of marital issues until kid(s) are in bed", etc.)
Blessings, sweet one!!!